History Main / TemporalParadox

* ''WesternAnimation/MeetTheRobinsons''. Let's see. If Goob made the catch and won, getting himself adopted and never becoming [[spoiler:the Bowler Hat Guy]], Lewis would never have learned that Goob became that person, and never bothered to prevent it. Yeah. And he wouldn't known not to create Doris.

* In the ''Film/BackToTheFuture'' movies, Doc Brown is very concerned with temporal paradoxes.

* In ''Film/BackToTheFuture'', Chuck Berry steals Johnny B. Goode from Marty (after hearing an incomplete performance over a 1950s payphone, no less), who learnt it from Berry in the first place.

* In the first story arc in ''Webcomic/BlackHole'', main character Diana Nox deals with a caveman who was mysteriously sent to the present. After sending him back to his proper time with her SexMagic, Diana inadvertently changes history due to teaching the caveman modern concepts of sexual relations and apparel (i.e. kissing, the missionary position and wearing lingerie) and him introducing those concepts to his mate.

* ''Infinity'' series:
** At one point, ''VisualNovel/{{Ever17}}'' features a time-travel attempt to SetRightWhatOnceWentWrong with an obvious fix. Unfortunately, this also undoes the events that triggered the attempt, resulting in [[https://static.tvtropes.org/pmwiki/pub/images/ever17_time_paradox.jpg a very unpleasant paradox]]. Warning. That link is hellishly disturbing.
** In several Bad Ends of ''VisualNovel/{{Remember11}}'', death of one of the main characters causes the story's StableTimeLoop to shatter, leading to them [[RetCon discovering themselves sometime before the exchanges started]] -- [[spoiler:[[DyingDream freezing to death in the plane's wreck]]]] for Kokoro, and [[spoiler:[[CuckooNest stuck in an asylum as "Enomoto"]]]] for Satoru.

[[folder:Web Video]]
* ''WebVideo/NightmareTime:'' In the episode "Killer Track", Miss Holloway is approached by Rose to help remove a curse that she received by listening to the titular Killer Track. Miss Holloway travels back in time to possess Rose's body, making it so that she was the one who heard the song, not Rose.

In ''VisualNovel/ZeroEscape'': [[spoiler:Phi is in possession of a Brooch that was passed onto her by her unknown mother. In one timeline in ''VisualNovel/ZeroTimeDilemma'', Diana sees Phi burn alive in the Incinerator, after which only her brooch is left. Afterwards, Sigma and Diana are trapped in the nuclear bomb shelter for 10 months, leading to her giving birth to twins, whom they name Phi and Delta. She and Sigma then use the transporter to send their twins back in time to the year 1904, as they do not have any food remaining in the shelter. Diana puts the Brooch she got from the incinerated Phi into the Transporter with the young Phi (The transporter creates an identical copy of one person that is then sent to a selected point in time in a selected timeline). The Phi that was sent back in time to 1904 first gets transported again ten months later to the year 2008, lives for 120 years, then literally raises herself in the year 2008 and gives the young Phi her brooch. This seemingly creates an ontological paradox: Diana received the Brooch from the incinerated Phi, after which Diana sends the brooch back in time to 1904 with Phi, who then passes the brooch on to 2008 Phi who then gets incinerated in ''ZTD'', and Diana sends the Brooch back again. Why the brooch doesn't degrade after being incinerated, sent back in time and then existing for 100 more years an infinite number of times is unknown, but that is generally a problem with ontological paradoxes, as they practically don't have an origin. And technically, most things that happen in ''Zero Escape'' are an ontological paradox.]]

* In ''VideoGame/ShadowHearts'', Yuri's TragicKeepsake, Anne's Cross, is the focal point of one of these. [[spoiler:He receives it from his dead mother, but gives it to one of his party members, Karin, in the second game. In the ending, Karin travels back in time, becoming amnesiac, and turns out to be Yuri's mother, who gives birth to Yuri and gives him the necklace upon her death, starting the loop all over again.]]

** The documentaries on the DVD set mention how the justification was that there's some entity that regulates time itself. The partial deletion over time of Marty, why both Jennifers fainted when they met each other, and why even with relatively major changes to the timeline, Marty's family, home, and association with Doc Brown and Jennifer remain largely the same. They wanted to explore this aspect, but couldn't find a way to incorporate it into the films without it being obtrusive. [[Wiki/{{Wikipedia}} The Other Wiki]] has more information [[http://en.wikipedia.org/wiki/Back_to_the_Future_timeline#Time_Travel_Theory here]].

* The Reversed Grandfather Paradox is lampshaded for all it's worth in ''Machinima/RedVsBlue'' when Church is send back in time and attempts to prevent the accident that started the entire time travel problem.

[[folder:Western Animation]]

[[/folder]]

!!Grandfather paradox examples:

[[folder:Anime and Manga]]
* ''LightNovel/DateALive'': Origami experiences one when she realizes that [[spoiler:she's the spirit that killed her parents, as she went back in time to kill the spirit that did so, but unintentionally killed them in front of her younger self in the process of facing a different spirit]].
* ''Anime/DragonBallZ'' follows the multiverse approach, as explained [[AllThereInTheManual in the manual]] by Creator/AkiraToriyama -- each timeline exists in a separate dimension, so if you go to the past and change something, nothing will happen when you go back to "your" future. It makes things a little more poignant for Future Trunks, who travels back in time knowing that changing the past won't affect ''his'' BadFuture, but still idealistic enough to believe he can help ''some'' other universe with his future knowledge. Toriyama's explanations suggest three alternative timelines, but fans have [[FanWank extrapolated a couple more to make sense of things]]:
** Line 1: The timeline we see in the anime and manga. This timeline's Cell is killed in larval form so that he doesn't terrorize that timeline, and the Trunks who grows up in that timeline is ''quite'' different from the one from the BadFuture who visits early on.
** Line 2: The native timeline of Future Trunks. That Trunks has no reason to think his actions in Line 1 will affect Line 2, but he ''does'' get strong enough from everything that happens in Line 1 that he can easily defeat the Androids ''and'' Cell once he returns to Line 2.
** Line 3: The native timeline of Future Cell, who kills that timeline's Trunks, steals his time machine, and becomes the BigBad of the saga in Line 1. Interestingly, Future Cell and Future Trunks originate in different timelines but arrive in the same one.
** Line 4: Extrapolated by fans noticing that in Line 3, Cell kills Trunks ''after'' he returns from the past. But this isn't the Trunks from Line 2, who survives to defeat that timeline's Androids, so the Trunks Cell killed must be a different Trunks, and this is the timeline he went to. The commonly accepted theory (suggested by the ''Daizenshuu'' guidebooks) is that Line 4 is exactly the same as Line 1 up until the point of Cell's discovery, at which point the androids are summarily defeated before Cell could absorb them. Most likely, Krillin never destroyed Bulma's deactivation switch in this timeline, which allowed them to be easily defeated (and then Trunks could take it back to Line 3 to defeat ''those'' androids).
** Line 5: Also extrapolated by fans, in the sense that Line 2 Cell ''would'' have visited this timeline had Line 2 Trunks not returned from Line 1 [[TrainingFromHell so ripped]] that he could defeat Cell before he could travel back in time. But things aren't great for this timeline -- Future Trunks has no idea about Cell until he encounters Future Cell in the past, and with no Future Cell, nobody has any reason kill ''that'' timeline's larval Cell before he becomes a threat, nor will the Trunks who visits Line 5 be strong enough to defeat his home timeline's Cell when he returns. There's a reason we're looking at Line 1.
* ''LightNovel/HaruhiSuzumiya'': Every instance of time travel in the stories (and there are many) invariably generates paradoxes like these. Characters go back in time to save themselves, information comes out of nowhere, etc., etc. Of course, no explanation is ever given in the books.
* ''Anime/YourName'' gets into one of these once the time travel aspect is revealed. Taki and Mitsuha have spent the last few weeks [[FreakyFridayFlip randomly swapping bodies]], until it abruptly stops happening. Taki tries to find Mitsuha, only to discover that [[spoiler:they're three years out of synch -- he's in 2016 while she died in 2013 when her town was destroyed by a fragmenting meteor]]. Armed with this knowledge, Taki tries to force one more mind-swap. [[spoiler:He succeeds and, working with Mitsuha and her friends, they ultimately manage to evacuate the town to safety, saving all.]] This has absolutely no effect on Taki or any of the other events of the movie, [[spoiler:except for the ending, where a now-living Mitsuha finally meets Taki face-to-face in 2022.]]
[[/folder]]

[[folder:Literature]]
!!By Author:
* Works by Creator/DouglasAdams:
** ''Franchise/TheHitchhikersGuideToTheGalaxy'' universe is full of this, particularly in the third book. A correction-fluid manufacturer tries to get an endorsement from a tragic poet and ends up preventing the tragedy that inspired him. A landmark cathedral is torn down to make way for an ion refinery, but escalating delays in the refinery's construction mean that in order to open on time they have to use time travel to start the project ever further back into the past. Eventually it started so far back in time that said cathedral was never built in the first place – making protests against its demolition strangely hollow, and postcards of it suddenly immensely valuable.
*** Worst of all are aorist rods, which provided power to the present by depleting the power reserves of the past ... when it was discovered ''those [[HypocriticalHumor bastards]] in the future were doing the exact same thing'', the rods and all knowledge of their manufacture was destroyed to stop what was already happening now from occurring in the future.
** The resolution to ''Literature/DirkGentlysHolisticDetectiveAgency'' involves a temporal paradox which one character explicitly points out has created an impossible situation. This is casually handwaved away by another character who states that it's no worse than any other paradox that exists in the universe, and that people will deal with it as they always have, which is to simply believe whatever is necessary for things to make sense.

!!By Title:
* In ''Literature/TheAnubisGates'' by Tim Powers, main character Brendon Doyle, a modern expert on the poet William Ashbless, ends up back in the 1800's during Ashbless' lifetime. When [[spoiler:Doyle ends up BECOMING Ashbless thanks to a [[FreakyFridayFlip body-snatching werewolf]] (don't ask), he publishes the poems from memory]]--which leaves us with the problem of how the poems were written in the first place. In fact, it actually freaks ''Doyle'' out, but he concludes that [[spoiler:as long as the poems exist, history will continue in its proper order, so he shouldn't sweat too much over it]].
* Creator/DavidWeber's ''Literature/TheApocalypseTroll'' has the characters discussing the theories about time travel -- one (it's not possible) has been disproved by the fact that one character just did, to arrive in the time of the discussion; the other two, that the future will be altered by what she did or that her presence has caused an alternate world to split off, can't be proved or disproved by anything they can do now. They end up assuming the alternate world and thereafter ignore the question.
* The ''Literature/{{Caretaker}}'' Trilogy has an interesting take on this: there are no alternate universes, and while changing the future/past is possible, doing anything that would create a paradox is impossible simply ''because'' it would create a paradox. It's said that there is some natural "force" that prevents paradoxes from occurring. Exactly how that works is not explained, because the protagonist apparently doesn't have the necessary education to understand the specifics.
* ''Franchise/TheDarkTower'':
** In ''Literature/TheDrawingOfTheThree,'' Roland kills the man who murdered Jake, who Roland met in ''Literature/TheGunslinger''. He spends the first part of ''Literature/TheWasteLands'' fighting off insanity because of the paradox this creates.
** To say nothing about what happens to Jake in the first part of ''Literature/TheWasteLands'', who is both alive and dead at the same time.
* It gets weird in the ''Franchise/DoctorWhoExpandedUniverse'', which features Literature/FactionParadox, a villain group whose [[PlanetOfHats hat]] is temporal paradoxes. In fact, part of their [[{{Cult}} initiation ritual]] involves traveling back in time and [[SelfMadeOrphan killing off your own ancestors]]. Yes, really.
** At one point, they infected the Third/Fourth Doctor with [[TheVirus Faction biodata]] during a regeneration that wasn't supposed to happen (when he was shot on Dust, instead of [[Recap/DoctorWhoS11E5PlanetOfTheSpiders the canon radiation poisoning on Metebelis Three]]), causing the Eighth Doctor to disrupt his own timeline so that the Third Doctor was shot on Dust, permitting the Faction to infect him with the biodata, which caused him to tinker with the past so he could be infected with the biodata... [[YourHeadASplode BOOM!]]
** And that's ''before'' you enter the [[EldritchLocation Eleven-Day Empire]], a place ''literally'' made of nonexistent time. Or the [[HumanoidAbomination Grandfather]] [[GrandfatherParadox Paradox]], the AnthropomorphicPersonification of [[FutureMeScaresMe all potential evil and despair]] in the Universe. Or the part where Gallifrey's history is repeatedly raped into oblivion.
** A broken timeship is the main setting of ''Vanderdeken's Children''. Initially, the broken ship is found in deep space and slowly repaired. Then a second ship, this one more functional, appears. Soldiers board the second ship and find clearly-marked instructions, which they copy and transmit to the scientists fixing the first ship. The second ship is attacked, heavily damaged, and sent back in time to deep space. The scientists successfully fix the first ship, and attempt to prevent the attack on the second, so they set the coordinates to capture it earlier, but they all get killed, and so the repaired ship makes its journey to be found by the soldiers... Until the Doctor arrives and gives the paradox a slight nudge and allowing it to unravel, it's locked in an eternal cycle without beginning or end.
* In ''Literature/{{Dragonlance}}'', Raistlin [[spoiler:kills Fistandantilus and usurps his soul, and then goes forth to succeed where Fistandantilus failed in traveling into the realm of the Gods. Since it was Fistandantilus' drifting soul that resulted from that first failure which saved Raistlin's life during his Test in the first place, I think we can all say that Raistlin pretty much screwed causality in the ear]].
* Time travel is forbidden in ''Literature/TheDresdenFiles'' because it might end up destroying the fabric of reality. Characters capable of seeing the future can't be specific about their visions for the same reason.
** The Gatekeeper, specifically, has a vision of something major in the Dresdenverse, and alerts Harry to it, in the most vague, roundabout way. Bob later explains he did this to avoid the entire universe going kaput. He also mentions that no one has ever caused a temporal paradox before, and you can tell by the way the universe keeps existing.
* Distilled to its purest form in Creator/FredricBrown's short story ''[[http://www.gutenberg.org/files/29948/29948-h/29948-h.htm Experiment]]''.
* Some argue that [[http://en.wikipedia.org/wiki/René_Barjavel René Barjavel's]] ''Le Voyageur imprudent'' is the [[UrExample first ever example]] of the grandfather paradox.
* Lazarus Long, protagonist of Creator/RobertAHeinlein's ''Literature/TimeEnoughForLove'' creates a time machine and argues that it would not be possible for him to change the past, because in doing so he would also change the future--in the essence, negating his own existence, or at least the details of it--and making his own journey into the past improbable at best, if not impossible.
* Creator/GregoryBenford's ''Timescape'' describes a unique, quantum-mechanical approach to Grandfather Paradoxes. If a time-travelling signal were to prevent its own transmission, the signal and everything involved in triggering it would be in an ''indeterminate'' state where it neither does, nor doesn't, occur -- like Schrödinger's Cat before the box is opened.
* The ''Literature/TimeScout'' novels avoid Temporal Paradox by the timeline including built-in safeguards; safeguards which are dangerous to time travelers. The most prominent are first, that you can't change ''anything'' that's important to the timeline--some improbable accident will occur to prevent it, no matter what you try--which is dangerous, as although some people, objects and events are obviously important to the timeline, there are [[ForWantOfANail even more that aren't obviously important, but just as crucial]]; and second, that if a time traveler ever arrives at a time where they already exist, the most recent version dies instantly to prevent them from doing anything to their past selves that would undermine their current presence.
* In Marion G. Harmon's ''Literature/WearingTheCape'', the Teatime Anarachist explains the rather unusual rules that do seem to eliminate the problem: there is a privileged Now, where his and everyone else's actions are real and affect things and can't be changed -- because they slip into the Past, which he can't change. The Future, on the other hand, is only the most possible future. He can interact with it and bring things back, but acts in the Now can still alter it.
* Larry Niven has an essay on why there is no time travel. Time travel is invented. you go back and change the past, the timeline flows until time travel is invented, someone goes back and changes the past. eventually time travel is invented- until someone changes the past so it results in a world where time travel is never invented.[[/folder]]

[[folder:Western Animation]]
* Naturally enough, ''WesternAnimation/BillAndTedsExcellentAdventures'' often courted this trope. One obvious example is the episode in which Bill and Ted neglect to buy Bill's father an antique railroad watch as a birthday present, to replace the one he lost as a child. Ted's initial plan is actually perfectly sound: [[StableTimeLoop take the original watch from Bill's father when he 'loses' it in the past, then give it to him in the present.]] This plan fails however, so they travel even further back in time to obtain the watch ''before'' Bill's father inherits it. Of course, this should mean that Bill's father wouldn't miss the watch in the first place, but the episode [[BellisariosMaxim simply ignores this]].
* The ''WesternAnimation/DannyPhantom'' [[MadeForTVMovie movie]] ''WesternAnimation/TheUltimateEnemy'' is one big temporal paradox. In the original timeline, Danny's family and friends are killed, he goes mad with grief and kills himself (people with a SplitPersonality can do that and survive), and his [[SuperpoweredEvilSide evil self]] terrorizes the world for ten years. Thanks to Danny and some timely interference by the DungeonMaster, this timeline was erased, but his evil self was in the past when it was erased, so he still exists even with the events that caused his existence never happening. His evil self even pointed out the paradox. "You don't get it, do you? I'm still here. ''I'' still exist. That means ''you'' still turn into me." The Observants mention something about him still being there because "he exists outside of time."
* Thankfully averted in ''WesternAnimation/DuckTales2017''. One episode has Dewey being dropped into the past with a younger Donald and Della Duck. At the end of their adventure, Dewey ''tries'' to warn Delila about her terrible fate, but both ducks stop him.
-->'''Dewey:''' Okay, but a gotta warn you what's gonna happen to you in the future!\\
(''Donald and Della's [[OhCrap eyes go wide]], quickly clamp his beak shut'')\\
'''Donald:''' No! Keep your mouth shut!\\
'''Della:''' No! Can't warn us about the future! You'll disrupt the timestream!\\
'''Donald:''' Have you watched any movies?!
* In ''WesternAnimation/InvaderZim'', an entire episode (Bad Bad Rubber Piggy) has one scene that demonstrates this perfectly: After GIR finds out that Zim intends to send a robot back to the past to destroy Dib, it leads to this classic line of dialogue:
-->'''GIR:''' Wait... if you destroy Dib in the past, then he won't ever be your enemy, so you won't have to send a robot back, so then he will be your enemy, so then you WILL have to send a robot BACK... ''(head explodes)''
* Starlight Glimmer's revenge plot in ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' results in this: she travels back in time to prevent the Sonic Rainboom that gave the Mane Six their Cutie Marks...to get revenge on them for foiling her actions in Our Town in the season premier, meaning she'd negate her own reason for going back in time in the first place. Though her and Twilight seem to be immune to the timeline changes. Unlike many events, this actually ''does'' cause serious issues: each change to the past she makes causes a BadFuture worse and worse than the last [[note]]Although the simple fact that Twilight Sparkle is able to visit several altered futures is left unexplained : Nightmare Moon's return was the first catastrophy which the main characters stopped, but no trace of it subsists in several alternate futures, ruled by villains who showed up ''after'' the Mare in the Moon. But WMG is probably here to solve this.[[/note]]
* In the rather TimeyWimeyBall finale of ''WesternAnimation/SamuraiJack'', [[spoiler:Ashi is Aku's biological daughter, and after she uses her powers to transport her and Jack into the past to kill Aku (right after Jack's past self is sent into the future) she pops out of existence because if Aku is dead then Ashi was never conceived. But if Ashi doesn't exist, then who transports Jack back in time to kill Aku?]] The OneHundredPercentCompletion ending to ''VideoGame/SamuraiJackBattleThroughTime'' would apparently retcon that [[spoiler:Ashi was able to remain intact after all, implied to be so that Jack could still travel back and stay in his own time]].
* ''WesternAnimation/SuperFriends''. In the ''Challenge'' episode, "Secret Origins Of The Super Friends," the Legion of Doom tries to change history by messing with the origins of Superman, Wonder Woman, and Green Lantern. Okay, but seeing as how much of Super Friends is based on Pre-''ComicBook/CrisisOnInfiniteEarths'' lore and hence Luthor's baldness and StartOfDarkness were both accidentally caused by Superman when he was Superboy, how can Luthor-- and as its founder, the Legion of Doom itself--exist if Superboy was never there to cause what happened to Luthor? Likewise, given his origins even Pre-Crisis involved someone copying Superman, how does Bizarro continue to exist as well? This also applies, to a lesser extent, to the others. Sinestro's crimes were exposed by Hal Jordan; maybe eventually, someone else would have, but it was Hal's newbie attitude that caused him to question an otherwise model Green Lantern; shift the timeframe and he maybe never meets the [=LoD=]. Most Cheetah origins have Wonder Woman involved in some way, at least some as Cheetah feeling challenged by her existence. Also, take Luthor grabbing Abin Sur's ring. That might get the Guardians' attention. Also, without those three, and especially Big S, would the SF have even formed, and since the [=LoD=] formed out of fear of this group…the list goes crazy on. Ah, everyone know time travelers are [[AWizardDidIt surrounded by a temporal bubble]] that prevents them from being affected by their own alterations in the timesteam. The real question is: if the Legion of Doom could see through time to spy on the "secret origins" of the heroes, how do they not know the entire Justice League's secret identities?

!!Ontological paradox examples:

[[folder:Anime and Manga]]
* ''Anime/DragonBallZ'': In ''Anime/DragonBallZBardockTheFatherOfGoku'', Bardock attempts to stop Freeza from destroying Planet Vegeta to prevent the creation of a Super Saiyan. [[spoiler:He fails.]] In the ''[[Anime/DragonBallEpisodeOfBardock Episode of Bardock]]'' spinoff it turns out that Bardock [[spoiler:wasn't killed in the explosion but was sent back in time to before the Saiyans discovered Planet Plant]]. He fights Chilled, [[spoiler:Freeza's ancestor]], and during the fight he [[spoiler: becomes a Super Saiyan]]. This means that Bardock [[spoiler:is the Super Saiyan of legend, and that Chilled was the one who passed the legend down to King Cold and Freeza]]. That in turn means that [[spoiler:Freeza destroyed Planet Vegeta because Bardock became a Super Saiyan when he fought Chilled]].
** What's more is that Freeza [[spoiler:ordered Dodoria to kill Bardock]] [[YouCantFightFate specifically because]] he feared [[spoiler:Bardock may [[SelfFulfillingProphecy become a Super Saiyan...]]]]
** Of course, this is all meant as a WhatIf story, and considering how time travel normally works in the series, Bardock may have simply created a separate AlternateTimeline where all of this is what happened instead.
* In ''[[LightNovel/HaruhiSuzumiya The Disappearance of Haruhi Suzumiya]]'', [[spoiler: while traveling in the past Kyon is stabbed by Ryoko Asakura. As he lies bleeding out on the ground, what appears to be a Kyon from the future comes with a Yuki and a Mikuru also from the future and rescues him. So, basically, Kyon only lived because he lived long enough to go and come back to save himself. He lived because he lived.]] My head hurts...
** Don't forget the information paradox with the knowledge of Mikuru's mole. Kyon didn't know Mikuru had the star-shaped mole until future!Mikuru showed it to him. Mikuru herself didn't know until Kyon told her about it. When future!Mikuru realizes this, she is understandably upset, thinking she messed something up.
** Or the "Endless Eight" story arc, which finds the central characters reliving the same eight day cycle 15,498 times (quite unbeknownst to anyone [[spoiler:but Yuki]]). They finally [[spoiler:break the cycle when Kyon suggests a suitable ending to their summer vacation to Haruhi]].
* In ''LightNovel/InvadersOfTheRokujyouma'', Theia gets the school Drama club to do a play she wrote about an ancient legend on her homeworld. Kotarou ends up with the starring role of the Blue Knight. This involves not only memorizing his lines, but actual training in ancient sword styles. When he ends up on said homeworld millennia ago, He takes on the Blue Knight's role for real in an attempt to avoid a paradox, using the same skills and even lines he learned for the play.
** And again, Kiriha takes Kotarou out on a date like the one she went with a boy she fell in love with ten years ago. Later, Kotarou ends up ten years in the past(on his way back from the previous adventure) and meets a girl he is unaware is actually a young Kiriha. He ends up taking her on the date Kiraha would revisit years later because that's the closest thing to a date he's ever been on.
* The sundial watch in ''LightNovel/HumanityHasDeclined'' exists in a cycle of being stolen and given away between [[NoNameGiven "Grandfather" and "Watashi"]], with no original in sight. Particularly noticeable since [[ItMakesSenseInContext the other paradoxes all turned into dogs]].
* ''Anime/TransformersArmada'', in the "Drift" episode. Starscream is blasted with the Requiem Blaster, then Highwire somehow apparently warps the kids back in time, but in an AlternateUniverse, where both the Autobots and Decepticons are imprisoned and slowly being digested within Unicron. Before he expires, Hot Shot reveals that the Minicons are actually Unicron's cells, and the Transformers were being used by them. Then the kids travel further back in time to when the Minicons were created. Here they tell them to escape from Cybertron, eventually resulting in them coming to Earth and all subsequent events in the story. Then, back in the present, Perceptor stops Thrust from blasting Starscream. Therefore, the kids had to go back in time to trigger the sequence of events that led them to Cybertron and ultimately the time travel event itself.
* ''Manga/TsubasaReservoirChronicle'' has several such paradoxes. One of the most noticeable is [[spoiler: Real!Syaoran, who is a living, breathing time paradox, what with being he's the son of his own clone. It's implied that the timestream was desperately trying to hold itself together, resulting in a few {{Stable Time Loop}}s to patch up other paradoxes, resulting in Real!Syaoran's existence. When everything is sorted out in the end and the multiverse is repaired, Clone!Syaoran and Clone!Sakura are {{RetGon|e}}ned from existence, and Real!Syaoran almost ceases to exist because if his clone never existed, then neither could he, and he only ever really existed in the first place because he went and [[RealityBreakingParadox broke causality]]. The same thing goes for Watanuki, who only started existing to fill out a hole that Syaoran went and made in the multiverse by time-traveling. Now they've both got to pay for the repairs, so Real!Syaoran exchanges his ability to stay in one world for very long for his right to continue existing, while Watanuki instead trades his ability to go anywhere ever except Yuuko's shop.]]

[[folder:Comic Books]]
* In ''ComicBook/AllNewAllDifferentAvengers'', the team makes sure to prevent this: [[spoiler:Kang ends up knocking the Sam Wilson Captain America and Jane Foster Thor three days into the future, making sure that Thor lost the hammer. Cap gets Jane back to the hammer where it fell three days prior and use it to return to the present, then proceed to ''weaponize'' Temporal Paradox to drive Kang out. At Iron Man's suggestion, Thor drops the present day hammer in a spot so that she can find it once more without construction crews finding it and trying (and failing) to move it]].
* ComicBook/BoosterGold only becomes Booster Gold because as Michael Carter, a janitor in a 25th-century superhero museum, he steals a timesphere belonging to the time master Rip Hunter. It later transpires that [[spoiler:Booster will father Rip Hunter and teach him everything he knows about time travel]]. So if he hadn't stolen the timesphere, the timesphere wouldn't have been there to steal in the first place. Augh. To complicate matters, [[spoiler:Rip has to train Booster to be a time master so that Booster can have trained ''him'' to be one when he was a little boy.]]
* In Pre-Crisis Franchise/{{Superman}} comics, all time travel works this way, which is why Superman's ability to time travel by exceeding the speed of light is not a GameBreaker; he can travel back to the past, but he can't successfully change anything. TheMovie ignores this.

[[folder:Comic Strips]]
* Unsuccessfully {{invoked|Trope}} and thereby {{subverted|Trope}} in ''ComicStrip/CalvinAndHobbes'': Calvin tries to travel two hours into the future so that he won't have to write the story they're supposed to be writing for school. But the future Calvin doesn't have it, because he was to busy time travelling to the future to actually write it. Then they both travel to one hour ago because they decide that that Calvin should have written it... but he refuses on the grounds that whatever they threaten to do to him, they'll be doing it to themselves. In the end, the two Calvins return to the future empty-handed, only two find that the two Hobbeses have written the story for them. When Calvin starts reading it out loud at school, it turns out to be a story about [[spoiler:his foolish time-travel while the tiger(s) save(s) the day]].\\
The timeline of this whole thing is a little paradoxical, but at least the object/information obtained has an origin.
[[/folder]]

[[folder:Fan Works]]
* ''Fanfic/EggmanGenerations'' has Eggman consider this when his younger self, as per the ending of Sonic Generations, consider going into teaching rather than world conquest. Despite this, Eggman notes that the decision hasn't affected his own existence.
* Link saving himself in ''[[FanficRecs/TheLegendOfZelda The Legend Of Zelda: The Return]]''.
[[/folder]]

[[folder:Literature]]
* The ultimate time paradox story is [[Creator/RobertAHeinlein Heinlein's]] ''Literature/AllYouZombies'', [[spoiler:in which the protagonist turns out to be hisheritthey's own mother, father, son, daughter, grandmother, grandfather, grandson, granddaughter, great-grandmother, great-grandfather, great-grandson, great-granddaughter, great-great-grandmother, great-great-grandfather, and so on, ad infinitum. Also hisheritthey's own recruiting officer to the Temporal Bureau]].
** [[http://www.xs4all.nl/~pot/scifi/byhisbootstraps.html Another Heinlein story]], ''Literature/ByHisBootstraps'', takes things nearly as far. Among other hijinks, the main character gets a book from the future, which he copies into another one (the same one, when it's new?) when it becomes too old and is falling apart. A good way to avoid an object-based ontological paradox.
* In ''Literature/ArtemisFowl and the Time Paradox'', [[spoiler:Opal Koboi from the past travels to the present, and possesses Artemis' mother, making her appear ill. This forces present day Artemis to travel back in time to get the cure from the past Artemis. Opal then uses Artemis returning to the present to return to a few days before the present to make Artemis' mother ill in the first place. Ironically, this is all so she can aquire the secret of time travel.]]
** Not to mention, [[spoiler:Artemis had foggy memories of the past. When he went back in time, he left a note for Mulch to open the trunk Artemis and Holly were locked in. Also, the Mulch and Artemis of the past had their minds wiped, and since Artemis' wipe was a blanket wipe, there were still several remaining facts about fairies. By travelling back in time, Artemis caused himself to discover the fairy race. Whoa.]]
* ''Franchise/DoctorWhoExpandedUniverse'':
** The ''Literature/NewSeriesAdventures'' novel ''The Stone Rose'', the Doctor analyses the dregs from a mysterious vial of liquid, in order to create the full vial of liquid and take it back in time.
** The information version appears in the ''Literature/DoctorWhoNewAdventures'' novel ''Happy Endings'', when the Doctor warns Music/TheIsleyBrothers against listening to any of their own songs that they haven't written yet while in 2010, because songs like that are always written by Time herself. O'Kelly Isley decides to hear "Summer Breeze" anyway. This being a fun anniversary story, the Doctor decides it's probably fine. (And we will ignore the fact that "Summer Breeze" was a cover of a song by Seals and Crofts.)
* "Time for an Experiment", a short story in ''Magazine/{{Dragon}}'' by Michael G. Ryan, the main character is an elven wizard who needs a specific magical watch for his time-travel experiments, and is surprised to be given it by a woman he doesn't know. He later finds her again, and she becomes his apprentice, but she insists she has no memory of their first meeting. He eventually realises that he's going to send her back in time to buy the watch and give it to him, something that is only possible because he both knows her and has the watch. It then gets even more complicated than that.
* In ''Flatterland'' (a SpinOffspring sequal to ''Literature/{{Flatland}}''), Victoria Line and the Space Hopper end up trapped in a black hole. They're rescued by slightly older versions of themselves with a portable white hole, producing both a reverse grandfather paradox and an object loop.
* In ''Literature/HarryPotterAndThePrisonerOfAzkaban'', [[spoiler:Harry and Hermione travel back in time for a number of reasons. During this time travel, Harry manages to save himself from dementors using an Expecto Patronum charm. The event is noted to have happened earlier in the book with Harry only glimpsing his mysterious saviour and thinking it looked a lot like his dad. Note that they are unaware of their problems they went back to fix being solved until after they travel back in time, thus making this not an example of the first.]]
* Chronos, the Incarnation of Time from Creator/PiersAnthony's ''Literature/IncarnationsOfImmortality'', is immune to this, to an extent. He cannot be balked by paradox, he remembers the original and the new timeline, though no one else does. The limit is that he cannot interfere with his own workings (the "Three Person Limit"). He can exist once, go back in time and change things, but he cannot go back in time and stop himself from changing things, thus the three person limit.
* [[spoiler:There's a human version of the object loop]] in ''Literature/{{Pyramids}}'', with [[spoiler:Dios (who frequently makes reference to a lack of memory very far back) being transported backwards through time to the beginning of Djelibeybi. The lack of wear-and-tear is explained by Dios using the time-destroying effects of the pyramids to reverse the effects of time on himself. There's also some Reverse-Grandfather involved, considering he persuaded the original founder of Djelibeybi to begin the Pyramid tradition, which in turn allowed Dios to live long enough to go back in time to persuade the founder and so on...]]
* Averted -- by the characters, no less -- in Creator/IsaacAsimov's short story ''The Red Queen's Race''. They wind up creating a StableTimeLoop instead. [[spoiler: A scientist conducts an experiment to send modern scientific texts back in time, translated into ancient Greek. His translator, fearing a Temporal Paradox, only translates the parts that would account for the oddly anachronistic scientific advances ''already in our ancient history'', like Hero's steam engine or the infamous Baghdad Battery.]]
* In Creator/HarryHarrison's ''[[Literature/TheStainlessSteelRat The Stainless Steel Rat Saves the World]]'', Jim comes home to find that sending He (that's the villain's name) to the time when Earth was about to be destroyed led him to launch the Time War, yet the Time War is the reason Jim got involved in the first place.
--> '''Jim''': The way I see it, He just bounces in a circle in time forever. Running from me, chasing me, running from me. . . . Arrrgh! When was he born? Where does he come from?\\
'''Coypu''': Those terms are meaningless in this sort of temporal relationship. He exists only within this time loop. If you wish to say it, though it is most imprecise, it would be fair to state that he was never born. The situation exists apart from time as we normally know it.
* Played with in the latest ''Literature/ThursdayNext'' book, where they find that despite the existence of the [[TimePolice Chronoguard]], no one has actually ''invented'' time travel yet, so they assume that the technology much have been sent from the future and eventually they'll find the spot on the timeline where someone invented it to [[StableTimeLoop close the gap]]. As one character describes it, it's like they're running the technology "off of borrowed credit." This causes trouble however, when the Chronoguard begins to realize that no one in the timeline ''ever'' invented time travel. The resulting paradox causes the system to unravel and gets rid of any further possibility of TimeTravel in the series (although it seems everyone in the populace has a RippleEffectProofMemory).
* PlayedForLaughs in ''Literature/XanthippicDialogues'', where a footnote explains that the really great poets' influence stretched backwards in time, which is how you can find [[JustForFun/TheZerothLawOfTropeExamples Shakespearean quotations]] in plays from the fifth century BC.
[[/folder]]

In ''VisualNovel/ZeroEscape'': [[spoiler: Phi is in posession of a Brooch that was passed onto her by her unknown mother. In one timeline in ''VisualNovel/ZeroTimeDilemma'', Diana sees Phi burn alive in the Incinerator, after which only her brooch is left. Afterwards, Sigma and Diana are trapped in the nuclear bomb shelter for 10 months, leading to her giving birth to twins, whom they name Phi and Delta. She and Sigma then use the transporter to send their twins back in time to the year 1904, as they do not have any food remaining in the shelter. Diana puts the Brooch she got from the incinerated Phi into the Transporter with the young Phi (The transporter creates an identical copy of one person that is then sent to a selected point in time in a selected timeline). The Phi that was sent back in time to 1904 first gets transported again ten months later to the year 2008, lives for 120 years, then literally raises herself in the year 2008 and gives the young Phi her brooch. This seemingly creates an ontological paradox: Diana received the Brooch from the incinerated Phi, after which Diana sends the brooch back in time to 1904 with Phi, who then passes the brooch on to 2008 Phi who then gets incinerated in ''ZTD'', and Diana sends the Brooch back again. Why the brooch doesn't degrade after being incinerated, sent back in time and then existing for 100 more years an infinite number of times is unknown, but that is generally a problem with ontological paradoxes, as they practically don't have an origin. And technically, most things that happen in ''Zero Escape'' are an ontological paradox.]]

* This possibly happening is why Della and Donald refuse to let Dewey (Della's son and Donald's nephew) warn them about the future in the ''WesternAnimation/Ducktales2017'' episode "Last Christmas".
-->'''Donald:''' NO! KEEP YOUR MOUTH SHUT!\\
'''Della:''' You ''can't'' warn us about our future, you'll disrupt the time stream!\\
'''Donald:''' Haven't you ever seen ''any'' movie?!
* In the first ''WesternAnimation/{{Futurama}}'' [[TheMovie movie]], the "paradox-free time travel" isn't quite paradox-free: [[spoiler:there remains an ontological paradox surrounding the origin of the name "Lars," as future-Fry chose that name when he realized that the injuries he sustained when Bender attempted to kill him made him Lars.]] From whence did the name come?
** Well, if we just accept that [[spoiler: there is no 'beginning' to the Lars and Fry cycle, then it all works out nicely. Fry says "Ow, my larynx", but it comes out as "Lars", at which point he realises "Oh hey, I look and sound like Lars now, I guess I ''am'' Lars!"]]
** Additionally, the temporal tattoo is an ontological paradox. At the end of the movie, Bender peels it off Lars's ass, takes it back in time, and puts it on the present Fry's ass. Thus, it was never actually created, and just loops through time eternally with no beginning or end.
** Fry's genetic material. Being his own [[spoiler: paternal grandfather]], the question is where exactly the information carried on his y-chromosome originated.
** One episode had Leela being the campaign manager of a Senator who had [[SetRightWhatOnceWentWrong traveled back in time to become the president of the world in order to prevent an apocalypse.]] He wins the election, but unfortunately invokes a paradox, which is explained by Bender. Since he changed the past, that would mean that he wouldn't have traveled back in time in the first place. The Senator disappears via ResetButton, and Nixon is reelected.
*** Not only that, he went back in time using the same method as in the aforementioned movie. So much for "paradox-free" time travel.
*** This brings along FridgeHorror, since this means that in about 20 years, there will be an apocalypse led by robots.
*** This same paradox occurs in "The Why of Fry" with the Scootie Puff, Sr. but there it works out just fine (Fry tells Nibbler in the past to give him a better escape craft during the Infosphere mission, the Nibblonians give him one, and he escapes before the quantum interface bomb sends the Infosphere to the other dimension, which is not what happened the first time and invalidates the event that made it possible for him to go back in time in the first place).
** Most if not all of the above is due to said "Paradox-Free" time travel actually being "Paradox-''correcting''" time travel: paradoxes come into existence repeatedly, but radiate enough doom that the universe actively kills them before they can do any damage. The only time this backfired on the universe was when the army of Benders was "corrected" all at the same time.
* ''WesternAnimation/{{Gargoyles}}'': Time travel always creates a StableTimeLoop:
** [[MagnificentBastard David Xanatos]] [[XanatosPlannedThisIndex planned out his fortune]] by time-travel. While in the past, he had a mundane coin and a note sent to his future self. The coin becomes a rare object worth a few thousand and the note contains instructions on how to invest the money.
** The Archmage goes back in time, rescues his past self from falling into a chasm, then schools him on how to acquire the objects that gave him the power to, among other things, go back in time and rescue his past self from falling into a chasm, then school him--
** The Phoenix Gate. It goes through all the events of the series until, to get it away from Puck, Goliath sends it to the distant past where it eventually gets discovered in the first place. The loop is looped.
* In the ''WesternAnimation/KimPossible'' three-parter "A Sitch in Time", future-Shego gives present-Shego a plan to use the Time Monkey to {{take over the world}}. Coming up with this sort of plan [[BrilliantButLazy on her own initiative]] isn't really like her -- but she didn't have to, she just had to remember what she'd been told and go back in time to repeat it to herself.
* In the ''WesternAnimation/MiloMurphysLaw'' episode, "Missing Milo", Milo, Cavendish and Dakota get stopped from running into a group of mutant pistachio monsters when a peach gets thrown at Cavendish which is then pocketed by Dakota; later after time traveling to 15 minutes in the past and seeing their past selves about to run into the mutants, Dakota hands the peach to Cavendish who uses it to stop themselves. This then leads to the two of them having a looping conversation about where the peach came from.
-->'''Cavendish:''' Wait a moment, where did you get that peach?\\
'''Dakota:''' Someone threw it at you earlier.\\
'''Cavendish:''' But that someone was me.\\
'''Dakota:''' I know.\\
'''Cavendish:''' But where did I get it?\\
'''Dakota:''' From me.\\
'''Cavendish:''' But where did you get it.\\
'''Dakota:''' Someone threw it at you earlier.\\
''(repeats)''
* This happens in the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode "It's About Time". Twilight Sparkle meets her future self, who tells her that she was able to get here because of the time spells located in the Star Swirl the Bearded wing of the Canterlot Archives. Later in the episode, she goes there (for entirely different reasons) and ends up using a time spell...to go back and tell herself about the time spells. Hmm, now where did she learn about the location in the first place?
** The whole episode is this. Past Twilight is so bewildered and amazed by the concept of time travel that she can't shut up, and future Twilight doesn't manage to tell her what the actual thing she's supposed to be averting is before she gets sucked back to the future: all past Twilight knows is that future Twilight was from the following Tuesday. So she spends the week panicking about it, ends up with all the injuries future Twilight had when she visited, and by Monday night concludes the only way to stop whatever will happen by Tuesday from happening is to stop time. [[spoiler:So she goes to the archives, but as Tuesday morning arrives, nothing happens, but she finds the time spell and goes back in time to warn herself not to worry about the future...]]
* The ''WesternAnimation/StarTrekTheAnimatedSeries'' "Yesteryear" revolves around a Reverse Grandfather Paradox in which Spock prevents his own death as a child. He doesn't do it quite right this time around, resulting in a slightly revised timeline when he gets home. Originally, [[spoiler: his pet had lived. This time, he arrives a moment late, and the pet dies.]]
* In ''WesternAnimation/TheTransformers'' episode "[[Recap/TransformersG1WarDawn War Dawn]]", the Aerialbots are sent back in time trying to destroy the Decepticons' time machine. This puts them back at the start of the war, right at the start of one of the very first Decepticon attacks. While they try to stay out of the way, the end up saving a insignificant, not important dock worker. As it turns out that insignificant dock worker was the un-upgraded Optimus Prime, both giving the Autobots a leader and keeping the Decepticons from winning an important first battle, getting an advantage over the Autobots and likely winning the war. It was Optimus who had the Aerialbots created in the first place.

* ''Film/Millennium1989'' concludes with a massive paradox barrelling its destructive way into the future whose time travel efforts caused it.
* Played with in ''Film/{{Primer}}''. As one of the characters says, "The ''last'' revision is apparently the one that counts." We find characters gradually losing their worries about causality; they wind up going back in time to relive the events of that same week in their original place -- apparently intending to do everything ''right'' this time. It appears that causing a paradox causes some kind of mild brain trauma to the time traveler involved. But then there's that other version of yourself that you drugged up and locked in the basement so you could replace him...
* ''Film/DejaVu2006'' contradicted itself on terms of this. First, it is implied that anything changed in past changes the present, as Doug causes the death of his partner, that was thought caused by the ferry explosion. Later, it is implied that the past has already been changed, as [[spoiler:the message "U CAN SAVE HER" in Claire's house was written by him]], but in the end, it is contradicted, because [[spoiler:if he prevented the explosion, he could never have been assigned to the case, and thus could never do the time travelling, and so on...]]
* French-Canadian movie based from a cult tv show ''Dans une galaxie près de chez vous 2'' featured a spatio-dimensional rip (shaped like a zipper) who goes to present Earth. The Capitain was able to chuck down a DVD with their plea ([[GreenAesop NOT to destroy the ozone layer]]) recorded on it. It backfired when the video got featured on ''Website/YouTube'' and ridiculed as "[[http://en.wikipedia.org/wiki/Star_Wars_Kid Star Wars Twit]]" (Being bad at pronounciation dosen't help). Nevertheless, it might have pushed a younger version of the Capitain to go into space, directly ''and'' indirectly setting the events of the show into place.

[[folder:Literature]]
* In ''Strange Attractors'' by Creator/WilliamSleator, almost any time travel to the past causes instability in the universe. As those instabilities add up, the entire universe can "go chaotic", essentially becoming a huge mass of paradoxes. The only noticeable effect of this is that electrical lighting flickers. In fact the timeline in the series is so fragile you can cause paradoxes by going so much as five minutes into the ''future''.
* In Ted Chiang's short story ''The Merchant and the Alchemist's Gate'', the titular gate can transport anyone exactly twenty years into the future, or twenty years back. This leads to increasingly more improbable shenanigans, starting with a StableTimeLoop involving a treasure map, and reaching its arguable peak when [[spoiler: a character's wife meets her husband's younger self in the past, takes him to the bedroom, and upon descovering his lack of the, er, skills that the husband has in the present, teaches him how to please a woman, over the course of weeks. It's also implied that the husband married her in the present because, when he saw her, she reminded him of the middle-aged woman who took his virginity.]]
* In Creator/LSpragueDeCamp's short story "A Gun for Dinosaur," four characters (two hunters and two guides) travel to the Cretaceous period for a dinosaur-hunting safari. One of the hunters, Holtzinger, is killed by a tyrannosaur, and the other, James, is blamed for his death because he recklessly fired the shots that woke the dinosaur up. Later, James, swearing revenge, tries to go back to just before the expedition arrived so he can kill the guides once they emerge from the time machine. Instead, the space-time continuum snaps him back to the present to prevent a paradox, killing him [[CruelAndUnusualDeath messily]].
* The novel ''Ice And Blood'' manages to produce a very strange reverse grandfather paradox. ZJ is a depressed, bipolar paranoid schizophrenic who has no memories of his childhood. He hates his life enough to deliberately break into a lab where time travel technology exists, he goes back to the past, and he kills his parents in the hopes he'll stop existing. Instead the violent and bloody deaths they suffer triggers his past self's mental illness. The obvious problem with this is that there's no guarantee that ZJ would suffer the exact same breakdown and block out his memories every time, nor is there any logical reason that depressed ZJ would ever go this route again when suicide would be significantly easier for him. It just doesn't work from a logic standpoint. (It's still a good read if you apply enough MST3KMantra to it.)
[[/folder]]

[[folder:Video Games]]
* Apparently, bringing a cube from the present to the future in ''VideoGame/PortalReloaded'' violates the laws of causality and creates a paradox, so when you try it, the cube simply disintegrates. Note that you can do the opposite thing: bring a cube from the future to the present. But then, if the present version of that cube is altered in any way, the future cube is RetGone. The player can freely travel between timelines without such problems.
[[/folder]]

* ''[[Webcomic/SomethingPositive Super Stupor's]]'' Clockstopper can change history with his "Time Punch". (And he'd [[http://www.superstupor.com/sust02132009.shtml rather be surfing]] [[ShoutOut TVTropes]] than fighting crime.)

* In ''Webcomic/DragonMango'' [[http://dragon-mango.com/comic/chapter03/dm03-28.htm you have to ride the rollercoaster-- because you're already getting off.]]
* In ''Webcomic/SailorMoonCosmosArc'', because of the Chibiusa of the 21st century traveling through time and being present in the final battle, she was reincarnated along with the other senshi. ''However'', because the other senshi were revived in the ''30th'' century, the Chibiusa that was born to Usagi and Mamoru never ended up traveling in time, therefore, unlike the other senshi, has no memories of her past life and has never awakened as a senshi. [[spoiler: It's because of an unconscious wish Usagi had that Chibiusa would never awaken as a senshi.]] There is one more twist to this: [[spoiler: the memories of the time-traveling Chibiusa were sealed inside the Pink Moon Crystal, so when she broke her brainwashing and started receiving her powers, she finally gained the memories of her past self]].

[[folder:Western Animation]]
* ''WesternAnimation/TheFairlyOddParents'' special, "The Secret Origin of Denzel Crocker". Timmy goes back in time to find out why Crocker was so miserable and to try to fix it. He finds out that as a child, Crocker ''himself'' had fairy godparents--and that they were Cosmo and Wanda, something that they don't remember--and figures out that he must've done something to lose his fairies. He tries to warn the young Crocker, but inadvertently ends up being the one who reveals the secret (with some help from both '70s Cosmo ''and'' modern Cosmo's stupidity). Furthermore, as Jorgen shows up to erase everyone's memories of there being fairies, young Crocker manages to get his hands on the DNA tracker that AJ had built so that they'd know when Crocker was around, ''and'' managed to get Cosmo's DNA to use in it, ''and'' managed to covertly write a memo on the back of it that fairy godparents exist without Jorgen noticing, allowing him to keep that knowledge after his memory of fairies was erased...which means that if Timmy had never interfered, Crocker would be neither miserable nor fairy-obsessed. However, whereas when Timmy left for the past, Crocker was using a very primitive and likely useless "fairy finder", the Crocker in the present that Timmy returned to was using the tracker that AJ had built, implying that he ''had'' created an alternate timeline, and leaving one to wonder what happened in the original timeline. Of course, considering it's explicitly stated in TheMovie that few kids keep their fairies past their first year, much less until adulthood when they would leave ''anyway'', we can guess...
** Well the original timeline seems to be that 70's Cosmo is that cause of Crocker losing him and Wanda. Timmy then stops this incident only for present day Cosmo to turn on the mic while Timmy is talking and cause the incident to happen anyway. While this doesn't explain how Crocker knew about the existence of fairies after his mind was wiped in the original timeline, since we don't see the original incident play out, we can just assume any number of reasons for that. (Perhaps he managed to write a note in that timeline too.)
** There was also a HistoricalInJoke to imply that it was an alternate timeline.
* ''WesternAnimation/JusticeLeague''
** Lord Chronos was at first a meek scientist who invented time travel. He used it to steal things from history that would not affect the timeline. Then his wife nagged him about his lack of imagination, and one trip to the Wild West later he decided that stealing the most famous items from history and setting himself up as master of space and time was the better way to go. Reality itself falls apart, so he decides to go to the beginning of time and do it all over again. Batman and Green Lantern manage to reset history. Batman also manages to create a close AndIMustScream moment by trapping him in an eternal loop of his wife's naggery.
** Time travel itself seems perfectly fine: Superman went to the future and the past, the Justice League went to [=WWII=], [[ComicBook/BoosterGold one of the team is from the future]], and the list goes on. ComicBook/VandalSavage notes that his time machine couldn't send him back to a period where he already existed, [[FridgeBrilliance which may be with good reason]]: in that episode, time was falling apart only when Batman was with his very old self.
[[/folder]]

%% Image and caption selected per Image Pickin' thread: https://tvtropes.org/pmwiki/posts.php?discussion=ob6p6eekrjh1snj177lquhbk
%% Please do not change or remove either without starting a new thread.

* ''LightNovel/DateALive'': Origami experiences one when she realizes that [[spoiler: she's the spirit that killed her parents, as she went back in time to kill the spirit that did so, but unintentionally killed them in front of her younger self in the process of facing a different spirit.]]

* Creator/GrantMorrison's legendarily complex and metafictional series ''ComicBook/TheInvisibles'' hinges itself on contradiction, and details several brainbending temporal paradoxes. It would perhaps be remiss to go into any of them here in any great detail. Basically, if you like that sort of thing, go read ''The Invisibles.''

* ''ComicBook/MightyMorphinPowerRangersShatteredGrid'' has a very ''painful'' one. [[spoiler:In the very first part, [[BigBad Lord Drakkon]] [[TheHeroDies kills Tommy Oliver]] to recharge the Green Crystal. However, since Tommy is massive integral to the Power Rangers timeline (as he would become the White Ranger, Red Zeo Ranger, first Red Turbo Ranger and the Black Dino Thunder Ranger), the Morphin' Grid decides to fix this little problem by dividing ''every Ranger era'' into its own separate universe just to prevent this.]]

[[folder:Fanfiction]]

[[folder:Film]]
* ''Film/{{Interstellar}}'' features a semi-temporal paradox, baring a similarity to the Reverse Grandfather Paradox. All of the scenarios in the Paradox are initiated by [[spoiler:Cooper and TARS manipulating space-time inside the Tesseract.]]
* Pretty much every film in the Franchise/PlanetOfTheApes franchise.

* ''Film/{{Frequency}}'' depicts basically the same situation as ''The Lake House''--[[SpaceIsMagic due to abnormal sunspot activity]], a police officer and his long-deceased father are able to communicate across a 30-year gulf of time over the same CB radio set. [[spoiler:The son first saves his father from dying in a firefighting mishap, only to discover that he died of lung cancer a few years later anyway. But he then manages to convince him to quit smoking.]]
* ''Film/DonnieDarko'': After sleepwalking away from the place where he was supposed to die, the eponymous character is caught in an unstable time loop that he must close. [[spoiler:When he moves himself and the jet engine that should have killed him back into the past, he closes the loop by dying in the way that he should have from the beginning, negating everything in the time loop.]] This causes everything that was changed by his time travel to exist outside of the normal timeline without affecting it. [[GainaxEnding Maybe.]] It's pointed out in the movie, more explicitly in the extended cut, that the cause of the time loop only happened because of the time loop; in the final timeline [[spoiler: the jet engine falls into the past and kills him for no reason whatsoever. In-universe speculation is that a deity or other being outside time caused it for reasons of their own]].
* The whole plot of the movie ''Film/TheButterflyEffect'' revolves around the main character's ability to travel back in time and change parts of his life. Every change causes [[spoiler:his brain to physically rewire itself with the new memories, though, and this causes intense pain for him.]]
* ''WesternAnimation/MeetTheRobinsons''. Let's see. If Goob made the catch and won, getting himself adopted and never becoming [[spoiler:the Bowler Hat Guy]], Lewis would never have learned that Goob became that person, and never bothered to prevent it. Yeah. And he wouldn't known not to create Doris.
* Averted in ''Film/TheTimeMachine2002'', where the time traveler attempts to save his fiancee, but she always dies on the same night no matter what he does. He travels into the future to find out why. [[spoiler: In the far, far future, he learns from a more evolved human that if he saved her he would not have the motivation to build his time machine. Apparently, a paradox is allowed if it doesn't prevent the time travel device's creation, though.]]

* Lazarus Long, protagonist of Creator/RobertAHeinlein's ''Literature/TimeEnoughForLove'' creates a time machine and argues that it would not be possible for him to change the past, because in doing so he would also change the future--in the essence, negating his own existence, or at least the details of it--and making his own journey into the past improbable at best, if not impossible.

* The ''Literature/TimeScout'' novels avoid Temporal Paradox by the timeline including built-in safeguards; safeguards which are dangerous to time travelers. The most prominent are first, that you can't change ''anything'' that's important to the timeline--some improbable accident will occur to prevent it, no matter what you try--which is dangerous, as although some people, objects and events are obviously important to the timeline, there are [[ForWantOfANail even more that aren't obviously important, but just as crucial]]; and second, that if a time traveler ever arrives at a time where they already exist, the most recent version dies instantly to prevent them from doing anything to their past selves that would undermine their current presence.
* ''Franchise/TheDarkTower''
** In ''Literature/TheDrawingOfTheThree,'' Roland kills the man who murdered Jake, who Roland met in ''Literature/TheGunslinger''. He spends the first part of ''Literature/TheWasteLands'' fighting off insanity because of the paradox this creates.
** To say nothing about what happens to Jake in the first part of ''Literature/TheWasteLands'', who is both alive and dead at the same time.

* In ''Literature/TheAnubisGates'' by Tim Powers, main character Brendon Doyle, a modern expert on the poet William Ashbless, ends up back in the 1800's during Ashbless' lifetime. When [[spoiler: Doyle ends up BECOMING Ashbless thanks to a [[FreakyFridayFlip body-snatching werewolf]] (don't ask), he publishes the poems from memory]]--which leaves us with the problem of how the poems were written in the first place. In fact, it actually freaks ''Doyle'' out, but he concludes that [[spoiler:as long as the poems exist, history will continue in its proper order, so he shouldn't sweat too much over it.]]
* Distilled to its purest form in Creator/FredricBrown's short story ''[[http://www.gutenberg.org/files/29948/29948-h/29948-h.htm Experiment]]''.

* Works by Creator/DouglasAdams
** ''Franchise/TheHitchhikersGuideToTheGalaxy'' universe is full of this, particularly in the third book. A correction-fluid manufacturer tries to get an endorsement from a tragic poet and ends up preventing the tragedy that inspired him. A landmark cathedral is torn down to make way for an ion refinery, but escalating delays in the refinery's construction mean that in order to open on time they have to use time travel to start the project ever further back into the past. Eventually it started so far back in time that said cathedral was never built in the first place – making protests against its demolition strangely hollow, and postcards of it suddenly immensely valuable.
*** Worst of all are aorist rods, which provided power to the present by depleting the power reserves of the past ... when it was discovered ''those [[HypocriticalHumor bastards]] in the future were doing the exact same thing'', the rods and all knowledge of their manufacture was destroyed to stop what was already happening now from occurring in the future.
** The resolution to ''Literature/DirkGentlysHolisticDetectiveAgency'' involves a temporal paradox which one character explicitly points out has created an impossible situation. This is casually handwaved away by another character who states that it's no worse than any other paradox that exists in the universe, and that people will deal with it as they always have, which is to simply believe whatever is necessary for things to make sense.
* In ''Literature/{{Dragonlance}}'', Raistlin [[spoiler: kills Fistandantilus and usurps his soul, and then goes forth to succeed where Fistandantilus failed in traveling into the realm of the Gods. Since it was Fistandantilus' drifting soul that resulted from that first failure which saved Raistlin's life during his Test in the first place, I think we can all say that Raistlin pretty much screwed causality in the ear.]]
* It gets weird in the ''Franchise/DoctorWhoExpandedUniverse'', which features Literature/FactionParadox, a villain group whose [[PlanetOfHats hat]] is temporal paradoxes. In fact, part of their [[{{Cult}} initiation ritual]] involves traveling back in time and [[SelfMadeOrphan killing off your own ancestors]]. Yes, really.
** At one point, they infected the Third/Fourth Doctor with [[TheVirus Faction biodata]] during a regeneration that wasn't supposed to happen (when he was shot on Dust, instead of [[Recap/DoctorWhoS11E5PlanetOfTheSpiders the canon radiation poisoning on Metebelis Three]]), causing the Eighth Doctor to disrupt his own timeline so that the Third Doctor was shot on Dust, permitting the Faction to infect him with the biodata, which caused him to tinker with the past so he could be infected with the biodata... [[YourHeadASplode BOOM!]]
** And that's ''before'' you enter the [[EldritchLocation Eleven-Day Empire]], a place ''literally'' made of nonexistent time. Or the [[HumanoidAbomination Grandfather]] [[GrandfatherParadox Paradox]], the AnthropomorphicPersonification of [[FutureMeScaresMe all potential evil and despair]] in the Universe. Or the part where Gallifrey's history is repeatedly raped into oblivion.
** A broken timeship is the main setting of ''Vanderdeken's Children''. Initially, the broken ship is found in deep space and slowly repaired. Then a second ship, this one more functional, appears. Soldiers board the second ship and find clearly-marked instructions, which they copy and transmit to the scientists fixing the first ship. The second ship is attacked, heavily damaged, and sent back in time to deep space. The scientists successfully fix the first ship, and attempt to prevent the attack on the second, so they set the coordinates to capture it earlier, but they all get killed, and so the repaired ship makes its journey to be found by the soldiers... Until the Doctor arrives and gives the paradox a slight nudge and allowing it to unravel, it's locked in an eternal cycle without beginning or end.

* The German RPG ''TabletopGame/TheDarkEye'' takes a similar approach in declaring time a dynamic, "healing" weave. An example to solve the grandfather paradox is to have the person get stranded in time, get a life, meet a woman, marry and have kids and thus becoming his own grandfather.

** Besides, [[spoiler: it's said that the Heroic Spirits are removed from the time axis and await their summonings in the Seat of Heroic Spirits. So, even in the case that Shirou actually ''did'' want to become a Heroic Spirit, as Archer is no longer bound by the rules of time, Shirou's death would not form a paradox and free him from his destiny. Archer's whole objective in UBW was both to attempt this plan anyway in the off-chance that it actually succeeded, and to make sure his past self didn't have to see his ideals betray him like he did.]]

* [[spoiler:Chuck Goodrich]] of ''Webcomic/TheAdventuresOfDrMcNinja'' traveled back from the future to stop a ZombieApocalypse. Then ''another'' of him showed up in order to stop a RobotUprising. And then more and more.
* The high cost to reality is invoked and elegantly resolved in [[http://www.penny-arcade.com/comic/2004/05/03/ this]] ''Webcomic/PennyArcade'' strip.
* In ''Webcomic/AmericanBarbarian'', [[http://www.ambarb.com/?p=417 Rick refuses to do anything that would prevent their births.]]
* In ''Webcomic/{{Homestuck}}'', most of the technology that can teleport an object thorough time and space are designed to prevent these paradoxes; appearifying an object that would cause a paradox instead creates a copy made of paradox ghost slime, which quickly collapses in a puddle of goo. It ''is'' possible to cause a grandfather paradox, but this creates a doomed AlternateTimeline marked for deletion - even if someone travels back to the main timeline somehow, they're still doomed to die.
** [[spoiler: Except for Davesprite, who seems to have dodged Fate's bullet by merging with a pre-existing entity in the main timeline, i.e. the kernelsprite.]]
* ''Webcomic/FaultyLogic'': Fox built a time machine for the sole purpose of traveling back in time to prevent himself from building a time machine, because he knew he would build a time machine and misuse it.
* In the ''Webcomic/{{Oglaf}}'' strip "Chronotherapy", a healer goes back in time to cure a plague before it devastates the kingdom, then goes to the queen to claim the StandardHeroReward she promised him. Since the plague never happened, the queen never hired him, so she doesn't know what he's talking about.

* Naturally enough, ''WesternAnimation/BillAndTedsExcellentAdventures'' often courted this trope. One obvious example is the episode in which Bill and Ted neglect to buy Bill's father an antique railroad watch as a birthday present, to replace the one he lost as a child. Ted's initial plan is actually perfectly sound: [[StableTimeLoop take the original watch from Bill's father when he 'loses' it in the past, then give it to him in the present.]] This plan fails however, so they travel even further back in time to obtain the watch ''before'' Bill's father inherits it. Of course, this should mean that Bill's father wouldn't miss the watch in the first place, but the episode [[BellisariosMaxim simply ignores this.]]

-->'''GIR:''' Wait... if you destroy Dib in the past, then he won't ever be your enemy, so you won't have to send a robot back, so then he will be your enemy, so then you WILL have to send a robot BACK... (head explodes)
* ''WesternAnimation/SuperFriends''. In the ''Challenge'' episode, "Secret Origins Of The Super Friends," the Legion of Doom tries to change history by messing with the origins of Superman, Wonder Woman, and Green Lantern. Okay, but seeing as how much of Super Friends is based on Pre-''ComicBook/CrisisOnInfiniteEarths'' lore and hence Luthor's baldness and StartOfDarkness were both accidentally caused by Superman when he was Superboy, how can Luthor-- and as its founder, the Legion of Doom itself--exist if Superboy was never there to cause what happened to Luthor? Likewise, given his origins even Pre-Crisis involved someone copying Superman, how does Bizarro continue to exist as well? This also applies, to a lesser extent, to the others. Sinestro's crimes were exposed by Hal Jordan; maybe eventually, someone else would have, but it was Hal's newbie attitude that caused him to question an otherwise model Green Lantern; shift the timeframe and he maybe never meets the [=LoD=]. Most Cheetah origins have Wonder Woman involved in some way, at least some as Cheetah feeling challenged by her existence. Also, take Luthor grabbing Abin Sur's ring. That might get the Guardians' attention. Also, without those three, and especially Big S, would the SF have even formed, and since the [=LoD=] formed out of fear of this group…the list goes crazy on. Ah, everyone know time travelers are [[AWizardDidIt surrounded by a temporal bubble]] that prevents them from being affected by their own alterations in the timesteam. The real question is: if the Legion of Doom could see through time to spy on the "secret origins" of the heroes, how do they not know the entire Justice League's secret identities?

* Thankfully averted in ''WesternAnimation/DuckTales2017''. One episode has Dewey being dropped into the past with a younger Donald and Della Duck. At the end of their adventure, Dewey ''tries'' to warn Delila her terrible fate, but both ducks stop him.
-->'''Dewey:''' Okay, but a gotta warn you what's gonna happen to you in the future!\\
(''Donald and Della's [[OhCrap eyes go wide]], quickly clamp his beak shut'')\\
'''Donald:''' No! Keep your mouth shut!\\
'''Della:''' No! Can't warn us about the future! You'll disrupt the timestream!\\
'''Donald:''' Have you watched any movies?!
* In the rather TimeyWimeyBall finale of ''WesternAnimation/SamuraiJack'', [[spoiler: Ashi is Aku's biological daughter, and after she uses her powers to transport her and Jack into the past to kill Aku (right after Jack's past self is sent into the future) she pops out of existence because if Aku is dead then Ashi was never conceived. But if Ashi doesn't exist, then who transports Jack back in time to kill Aku?]] The OneHundredPercentCompletion ending to ''VideoGame/SamuraiJackBattleThroughTime'' would apparently retcon that [[spoiler: Ashi was able to remain intact after all, implied to be so that Jack could still travel back and stay in his own time.]]

* ''Anime/DragonBallZ'': In ''Anime/DragonBallZBardockTheFatherOfGoku'', Bardock attempts to stop Freeza from destroying Planet Vegeta to prevent the creation of a Super Saiyan. [[spoiler: He fails.]] In the ''[[Anime/DragonBallEpisodeOfBardock Episode of Bardock]]'' spinoff it turns out that Bardock [[spoiler: wasn't killed in the explosion but was sent back in time to before the Saiyans discovered Planet Plant.]] He fights Chilled, [[spoiler: Freeza's ancestor]], and during the fight he [[spoiler: becomes a Super Saiyan.]] This means that Bardock [[spoiler: is the Super Saiyan of legend, and that Chilled was the one who passed the legend down to King Cold and Freeza.]] That in turn means that [[spoiler: Freeza destroyed Planet Vegeta because Bardock became a Super Saiyan when he fought Chilled.]]
** What's more is that Freeza [[spoiler: ordered Dodoria to kill Bardock]] [[YouCantFightFate specifically because]] he feared [[spoiler:Bardock may [[SelfFulfillingProphecy become a Super Saiyan...]]]]
** Of course, this is all meant as a WhatIf story, and considering how time travel normally works in the series, Bardock may have simply created a separate AlternateTimeline where all of this is what happened instead.
* The sundial watch in ''LightNovel/HumanityHasDeclined'' exists in a cycle of being stolen and given away between [[NoNameGiven "Grandfather" and "Watashi"]], with no original in sight. Particularly noticeable since [[ItMakesSenseInContext the other paradoxes all turned into dogs]].

* In ''LightNovel/InvadersOfTheRokujyouma'', Theia gets the school Drama club to do a play she wrote about an ancient legend on her homeworld. Kotarou ends up with the starring role of the Blue Knight. This involves not only memorizing his lines, but actual training in ancient sword styles. When he ends up on said homeworld millennia ago, He takes on the Blue Knight's role for real in an attempt to avoid a paradox, using the same skills and even lines he learned for the play.
** And again, Kiriha takes Kotarou out on a date like the one she went with a boy she fell in love with ten years ago. Later, Kotarou ends up ten years in the past(on his way back from the previous adventure) and meets a girl he is unaware is actually a young Kiriha. He ends up taking her on the date Kiraha would revisit years later because that's the closest thing to a date he's ever been on.

* In ''ComicBook/AllNewAllDifferentAvengers'', the team makes sure to prevent this: [[spoiler:Kang ends up knocking the Sam Wilson Captain America and Jane Foster Thor three days into the future, making sure that Thor lost the hammer. Cap gets Jane back to the hammer where it fell three days prior and use it to return to the present, then proceed to ''weaponize'' Temporal Paradox to drive Kang out. At Iron Man's suggestion, Thor drops the present day hammer in a spot so that she can find it once more without construction crews finding it and trying (and failing) to move it.]]

* Unsuccessfully {{invoked|Trope}} and thereby {{subverted|Trope}} in ''ComicStrip/CalvinAndHobbes'': Calvin tries to travel two hours into the future so that he won't have to write the story they're supposed to be writing for school. But the future Calvin doesn't have it, because he was to busy time travelling to the future to actually write it. Then they both travel to one hour ago because they decide that that Calvin should have written it... but he refuses on the grounds that whatever they threaten to do to him, they'll be doing it to themselves. In the end, the two Calvins return to the future empty-handed, only two find that the two Hobbeses have written the story for them. When Calvin starts reading it out loud at school, it turns out to be a story about [[spoiler: his foolish time-travel while the tiger(s) save(s) the day.]]\\
\\

[[folder:Fanfiction]]

* Another Creator/SandraBullock film, ''Film/{{Premonition}}'', [[PlayingWithATrope mixes this trope]] with YouCantFightFate: [[spoiler:Linda's attempts to prevent her husband's death cause it, but she does get pregnant before he dies, and prevents herself from going crazy and getting committed,]] which she could not have done had she not had the premonitions of the future.

-->'''Technician:''' It would have gone faster if you had written it [the note] yourself
-->'''Carlin:''' Yeah, then I recognize my own hand writing and the universe explodes.
* ''Film/TheTerminator'': Fathering the guy who will send you back in time counts, too. Also, where did the message about how "the future is not set" originate? Chronologically, Kyle first gave it to Sarah in 1984 as a message Future-John had sent with him when he sent him back in time. Then Sarah decides to teach it to present-John when he is a child so that he will have the message to send. So she gives the message to John, who gives it to Kyle, who goes back in time and gives it to her, who gives it to John, who gives it to Kyle, who goes back in time and gives it to her, who oh look I've gone cross-eyed.

* ''Film/{{Timecrimes}}'' could have been renamed ''Ontological Paradox: TheMovie''. The protagonist travels backwards in time, and ultimately ends up responsible for the events that caused him to travel back in time.
* In ''Film/TheTimeMachine2002'', the uber-Morlock explains, "You built your time machine because of Emma's death. If she had lived it would never have existed, so how could you use your time machine to go back and save her?"
* ''[[http://www.imdb.com/title/tt0498567/ Summer Time Machine Blues]]'' is a Japanese film that starts with a group of high school students on a hot summer day stumbling upon a time machine and using it to prevent the remote control for their air conditioner from fizzling out due to a spilled coke can. ''HilarityEnsues''.

---> '''Spock:''' Excuse me, Admiral. But weren't those a birthday gift from Dr. [=McCoy=]?
---> '''Kirk:''' And they will be again. That's the beauty of it.

* ''Film/{{Predestination}}'', being an adaptation of the below-mentioned ''Literature/AllYouZombies'', has the temporal police protagonist [[spoiler: being his/her own father/mother/recruiter, and the very person s/he is hunting, as s/he sleeps with his/her future self, has a baby who is abducted, ends up meeting his/her recruiter at a bar to join the temporal police, runs into his/her past self on a mission, impregnates her/him with... her/himself, who is taken from her/him after birth and left at an orphanage, then goes to hunt the so called 'Fizzle Bomber', only to eventually find that said criminal is his/her future self, having gone mad.]]

* Chronos, the Incarnation of Time from Creator/PiersAnthony's ''Literature/IncarnationsOfImmortality'', is immune to this, to an extent. He cannot be balked by paradox, he remembers the original and the new timeline, though no one else does. The limit is that he cannot interfere with his own workings (the "Three Person Limit"). He can exist once, go back in time and change things, but he cannot go back in time and stop himself from changing things, thus the three person limit.
* The ultimate time paradox story is [[Creator/RobertAHeinlein Heinlein's]] ''Literature/AllYouZombies'', [[spoiler: in which the protagonist turns out to be hisheritthey's own mother, father, son, daughter, grandmother, grandfather, grandson, granddaughter, great-grandmother, great-grandfather, great-grandson, great-granddaughter, great-great-grandmother, great-great-grandfather, and so on, ad infinitum. Also hisheritthey's own recruiting officer to the Temporal Bureau.]]

* Averted -- by the characters, no less -- in Creator/IsaacAsimov's short story ''The Red Queen's Race''. They wind up creating a StableTimeLoop instead. [[spoiler: A scientist conducts an experiment to send modern scientific texts back in time, translated into ancient Greek. His translator, fearing a Temporal Paradox, only translates the parts that would account for the oddly anachronistic scientific advances ''already in our ancient history'', like Hero's steam engine or the infamous Baghdad Battery.]]

* Played with in the latest ''Literature/ThursdayNext'' book, where they find that despite the existence of the [[TimePolice Chronoguard]], no one has actually ''invented'' time travel yet, so they assume that the technology much have been sent from the future and eventually they'll find the spot on the timeline where someone invented it to [[StableTimeLoop close the gap]]. As one character describes it, it's like they're running the technology "off of borrowed credit." This causes trouble however, when the Chronoguard begins to realize that no one in the timeline ''ever'' invented time travel. The resulting paradox causes the system to unravel and gets rid of any further possibility of TimeTravel in the series (although it seems everyone in the populace has a RippleEffectProofMemory).

* In ''Flatterland'' (a SpinOffspring sequal to ''Literature/{{Flatland}}''), Victoria Line and the Space Hopper end up trapped in a black hole. They're rescued by slightly older versions of themselves with a portable white hole, producing both a reverse grandfather paradox and an object loop.

* ''Franchise/DoctorWhoExpandedUniverse''
** The ''Literature/NewSeriesAdventures'' novel ''The Stone Rose'', the Doctor analyses the dregs from a mysterious vial of liquid, in order to create the full vial of liquid and take it back in time.
** The information version appears in the ''Literature/DoctorWhoNewAdventures'' novel ''Happy Endings'', when the Doctor warns Music/TheIsleyBrothers against listening to any of their own songs that they haven't written yet while in 2010, because songs like that are always written by Time herself. O'Kelly Isley decides to hear "Summer Breeze" anyway. This being a fun aniversary story, the Doctor decides it's probably fine. (And we will ignore the fact that "Summer Breeze" was a cover of a song by Seals and Crofts.)
* "Time for an Experiment", a short story in ''Magazine/{{Dragon}}'' by Michael G. Ryan, the main character is an elven wizard who needs a specific magical watch for his time-travel experiments, and is surprised to be given it by a woman he doesn't know. He later finds her again, and she becomes his apprentice, but she insists she has no memory of their first meeting. He eventually realises that he's going to send her back in time to buy the watch and give it to him, something that is only possible because he both knows her and has the watch. It then gets even more complicated than that.

* Trying to understand a complicated series of events in ''Webcomic/IrregularWebcomic'' seems to lead to this conclusion. Two characters are captured for OrganTheft purposes. Their future selves come to save them, but end up being captured as well. The original pair having their organs stolen survive by stealing the organs from their future selves, but eventually come across their original organs, and put those in them as well so that when their organs are stolen, only the spares are taken. [[http://irregularwebcomic.net/1871.html It's all very complicated]]. Of course [[spoiler: the characters end playing a part in destroying the universe by destroying the only time machine in existence instead of using it to become their future selves.]]

* From ''Webcomic/BobAndGeorge'', [[http://www.bobandgeorge.com/archives/010619c this]] ontological paradox shows the time-traveling X and Bass giving Dr. Light and Dr. Wily the ideas to create them in the first place.
* In ''Webcomic/{{Educomix}}'', two objects--Jessica's mask and Dave's fez--literally come from nowhere, having been given to their original owners by people from the future. [[spoiler:This causes a "Time Fart", which drains energy from other universes to keep the paradox in place.]]
* In ''Webcomic/EightBitTheater'', [[http://www.nuklearpower.com/2005/03/26/episode-532-20-power-loaders-vs-20-alien-queens/ Thief comes up with a plan by watching a future Red Mage carry it out.]] Red Mage immediately wonders about the paradoxical implications.
** Later, [[http://www.nuklearpower.com/2006/01/21/episode-651-thief-of-time/ Thief steals his class change from his future self]], only to later lose it when [[http://www.nuklearpower.com/2009/09/19/episode-1174-oh-thats-what/ his past self steals it from him]]. This class change has no origin.
** Red Mage also accuses [[spoiler:Chaos]] of having an unworkable plan because of a variant on this. [[spoiler:Chaos intends to destroy all of space and time which would destroy all the events leading up to his being summoned to destroy all of space and time]]. (Reaction: [[spoiler: I'd better not create a temporal paradox! I'd hate it if everything were destroyed the way I wanted it to be destroyed!]])

* In ''Webcomic/{{Jack|DavidHopkins}}'', [[spoiler: Drip]] unwittingly gets a chance at one, but he blows it and closes a StableTimeLoop instead. [[spoiler: The Devil offers to trade Drip the scarf his mother wore in life in exchange for the murder of a married couple. Drip obliges and goes to kill their infant son, too, but the Devil tells him not to; instead, Drip decides to leave some disturbing imagery for the police by leaving the baby among the scattered carnage of what's left of the wife. It's not until Drip sets him down that he realizes that the people he brutally murdered were his mother and father, the crying baby looking up at him is his infant self. Drip is horrified to realize that not only did he actually kill his parents, he's also the reason he was sent to live with the grandmother who's been sexually abusing him all his life (and, having died and ended up in the area of Hell that Drip rules, ''is still doing it''). The Devil points out that time works funny in Hell; Drip could have prevented it all if he had just chosen not to murder two strangers for a scarf.]]

* This happens in the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode "It's About Time". Twilight Sparkle meets her future self, who tells her that she was able to get here because of the time spells located in the Star Swirl the Bearded wing of the Canterlot Archives. Later in the episode, she goes there (for entirely different reasons) and ends up using a time spell...to go back and tell herself about the time spells. Hmm, now where did she learn about the location in the first place?
** The whole episode is this. Past Twilight is so bewildered and amazed by the concept of time travel that she can't shut up, and future Twilight doesn't manage to tell her what the actual thing she's supposed to be averting is before she gets sucked back to the future: all past Twilight knows is that future Twilight was from the following Tuesday. So she spends the week panicking about it, ends up with all the injuries future Twilight had when she visited, and by Monday night concludes the only way to stop whatever will happen by Tuesday from happening is to stop time. [[spoiler:So she goes to the archives, but as Tuesday morning arrives, nothing happens, but she finds the time spell and goes back in time to warn herself not to worry about the future...]]
* The ''WesternAnimation/StarTrekTheAnimatedSeries'' "Yesteryear" revolves around a Reverse Grandfather Paradox in which Spock prevents his own death as a child. He doesn't do it quite right this time around, resulting in a slightly revised timeline when he gets home. Originally, [[spoiler: his pet had lived. This time, he arrives a moment late, and the pet dies.]]
* In ''WesternAnimation/TheTransformers'' episode "[[Recap/TransformersG1WarDawn War Dawn]]", the Aerialbots are sent back in time trying to destroy the Decepticons' time machine. This puts them back at the start of the war, right at the start of one of the very first Decepticon attacks. While they try to stay out of the way, the end up saving a insignificant, not important dock worker. As it turns out that insignificant dock worker was the un-upgraded Optimus Prime, both giving the Autobots a leader and keeping the Decepticons from winning an important first battle, getting an advantage over the Autobots and likely winning the war. It was Optimus who had the Aerialbots created in the first place.

* This possibly happening is why Della and Donald refuse to let Dewey (Della's son and Donald's nephew) warn them about the future in the ''WesternAnimation/Ducktales2017'' episode "Last Christmas".
-->'''Donald:''' NO! KEEP YOUR MOUTH SHUT!\\
'''Della:''' You ''can't'' warn us about our future, you'll disrupt the time stream!\\
'''Donald:''' Haven't you ever seen ''any'' movie?!

* [[spoiler:There's a human version of the object loop]] in ''Literature/{{Pyramids}}'', with [[spoiler:Dios (who frequently makes reference to a lack of memory very far back) being transported backwards through time to the beginning of Djelibeybi. There's also some Reverse-Grandfather involved, considering he persuaded the original founder of Djelibeybi to begin the Pyramid tradition, which in turn allowed Dios to live long enough to go back in time to persuade the founder and so on...]]

** ''Franchise/TheHitchhikersGuideToTheGalaxy'' universe is full of this, particularly in the third book. A correction-fluid manufacturer tries to get an endorsement from a tragic poet and ends up preventing the tragedy that inspired him. A landmark cathedral is torn down to make way for a refinery, but in order to open on time they had to start construction so far back in time that said cathedral was never built making protests against its demolition strangely moot.
*** Worst of all are aorist rods, which provided power to the present by depleting the power reserves of the past ... when it was discovered ''those [[HypocriticalHumor bastards]] in the future were doing the exact same thing,'' the rods and all knowledge of their manufacture was destroyed to stop what was already happening now from occurring in the future.

-->-- ''[[VideoGame/LegacyOfKain Legacy of Kain: Soul Reaver 2]]''

*** This is generally accepted; however, it has been shown that Doctor Doom has invented technology that allows this rule to be broken in PAD's Comicbook/XFactor run.

** One run of ''Comicbook/{{Thunderbolts}}'' ended with the present-Thunderbolts meeting the past versions of themselves. Fixer killed his own past self, and the universe promptly began collapsing. [[spoiler: Fixer resolved it by having himself de-aged and his memories erased, in order to replace himself in the past. He thereby condemned himself to live in an infinite loop, reliving the same period of time over and over for eternity.]]

* Creator/GrantMorrison's legendarily complex and metafictional series ''Comicbook/TheInvisibles'' hinges itself on contradiction, and details several brainbending temporal paradoxes. It would perhaps be remiss to go into any of them here in any great detail. Basically, if you like that sort of thing, go read ''The Invisibles.''

* ''WesternAnimation/SuperFriends''. In the ''Challenge'' episode, "Secret Origins Of The Super Friends," the Legion of Doom tries to change history by messing with the origins of Superman, Wonder Woman, and Green Lantern. Okay, but seeing as how much of Super Friends is based on Pre-''Comicbook/CrisisOnInfiniteEarths'' lore and hence Luthor's baldness and StartOfDarkness were both accidentally caused by Superman when he was Superboy, how can Luthor-- and as its founder, the Legion of Doom itself--exist if Superboy was never there to cause what happened to Luthor? Likewise, given his origins even Pre-Crisis involved someone copying Superman, how does Bizarro continue to exist as well? This also applies, to a lesser extent, to the others. Sinestro's crimes were exposed by Hal Jordan; maybe eventually, someone else would have, but it was Hal's newbie attitude that caused him to question an otherwise model Green Lantern; shift the timeframe and he maybe never meets the [=LoD=]. Most Cheetah origins have Wonder Woman involved in some way, at least some as Cheetah feeling challenged by her existence. Also, take Luthor grabbing Abin Sur's ring. That might get the Guardians' attention. Also, without those three, and especially Big S, would the SF have even formed, and since the [=LoD=] formed out of fear of this group…the list goes crazy on. Ah, everyone know time travelers are [[AWizardDidIt surrounded by a temporal bubble]] that prevents them from being affected by their own alterations in the timesteam. The real question is: if the Legion of Doom could see through time to spy on the "secret origins" of the heroes, how do they not know the entire Justice League's secret identities?

* Comicbook/BoosterGold only becomes Booster Gold because as Michael Carter, a janitor in a 25th-century superhero museum, he steals a timesphere belonging to the time master Rip Hunter. It later transpires that [[spoiler:Booster will father Rip Hunter and teach him everything he knows about time travel]]. So if he hadn't stolen the timesphere, the timesphere wouldn't have been there to steal in the first place. Augh. To complicate matters, [[spoiler:Rip has to train Booster to be a time master so that Booster can have trained ''him'' to be one when he was a little boy.]]

In Zero Escape: [[spoiler: Phi is in posession of a Brooch that was passed onto her by her unknown mother. In one timeline in Zero Time Dilemma, Diana sees Phi burn alive in the Incinerator, after which only her brooch is left. Afterwards, Sigma and Diana are trapped in the nuclear bomb shelter for 10 months, leading to her giving birth to Phi and Sigma. She and Sigma then use the transporter to send their twins back in time to the year 1904, as they do not have any food remaining in the shelter. Diana puts the Brooch she got from the incinerated Phi into the Transporter with the young Phi (The transporter creates an identical copy of one person that is then sent to a selected point in time in a selected timeline). The Phi that was sent back in time to 1904 first gets transported again ten months later to the year 2008, lives for 120 years, then literally raises herself in the year 2008 and gives the young Phi her brooch. This seemingly creates an ontological paradox: Diana received the Brooch from the incinerated Phi, after which Diana sends the brooch back in time to 1904 with Phi, who then passes the brooch on to 2008 Phi who then gets incinerated in ZTD, and Diana sends the Brooch back again. Why the brooch doesn't degrade after being incinerated, sent back in time and then existing for 100 more years an infinite number of times is unknown, but that is generally a problem with ontological paradoxes, as they practically don't have an origin. And technically, most things that happen in Zero Escape are technically an ontological paradox.]]

* In [[http://faultylogic.comicgenesis.com/d/20071006.html this]] ''WebComic/FaultyLogic'' comic the main character builds a time machine to steal ideas for comics from his future self, only to have them stolen by his past self several seconds later. In essence, these ideas only exist for several seconds, over and over again.

* In ''WickedPowered'', much like the "All You Zombies" example, the main character becomes both of his own parents through time travel, gender-bending, and amnesia. His DNA therefore has no origin, and he is immortal because of this.

* In the WesternAnimation/MiloMurphysLaw episode, "Missing Milo", Milo, Cavendish and Dakota get stopped from running into a group of mutant pistachio monsters when a peach gets thrown at Cavendish which is then pocketed by Dakota; later after time traveling to 15 minutes in the past and seeing their past selves about to run into the mutants, Dakota hands the peach to Cavendish who uses it to stop themselves. This then leads to the two of them having a looping conversation about where the peach came from.

* The fear of this appears to be the reason why Comicbook/DoctorStrange, having traveled to the distant past and witnessing the Comicbook/FantasticFour having traveled to the same time and place for their own reason, is very reluctant to reveal himself to them. He has befriended them in the present, or rather ''his'' present, but the FF are from an earlier point in time and haven't met him yet.

* In ''MegamanStarForceOrion'', Amaya and Taisaka decide to go back in time to prevent Kiri from making contact with the Ice Goddess Talisman. With the help of the UMA Fire, they reach the year in which Kiri is exiled from her home. Fire then brings them 2 years forward in time, and Taisaka and Amaya meet Tagekai, who reveals that Taisaka was originally a member of Tri-Clan. This causes Taisaka to break down as Amaya abandons Taisaka, soon meeting Takeshi's former self. Takeshi later reveals he has memories of everything that occurred as he was 66, as he is trapped in that age. Taisaka changes herself by telling her younger self not to fight Tagekai which causes her to become exiled. Amaya and Taisaka bring Kiri to the Omnikron Temple, and Amaya meets Eidaya, explaining everything. This creates a major time paradox, which causes the already fragile sands of time to become even more fragile. Soon Amaya returns to the past, meeting his father, who realizes that Amaya is Amaya, and he travels after him. As Amaya tries to fix things in Tri-Clan, Takeshi reveals he killed Taisaka, and Daisuke King, a Time Traveling Kamen Rider, shows up and brings Amaya to the present. He warns Amaya that Ryo is about to be killed by a Shinigami named Albano, and if this were to happen, the future would be corrupt, as Takeshi would cease to exist in the present. At the same time, Amaya's father plans to force time into 11:60 PM on December 24th. Finally, Taisaka travels to the present from the past, creating a temporal corruption where memory demons overcome the present world and attempt to end the world. Time is eventually reset with the use of the Stolen Pocketwatch from the very first episode.

* Time Travel is rare in ''TabletopGame/{{Warhammer 40000}}'', but [[HyperspaceIsAScaryPlace the Warp]] does strange things sometimes, which may result in a ship setting out to answer what turns out to be its own distress signal. In another example, one kleptomaniac Ork Warboss was sent back through time via warp-storm, met up with his past self, and [[InsaneTrollLogic killed his temporal doppelganger so he could have two copies of his favorite gun]]. The resulting confusion stopped the Waaagh! in its tracks.

* In ''WebComic/SailorMoonCosmosArc'', because of the Chibiusa of the 21st century traveling through time and being present in the final battle, she was reincarnated along with the other senshi. ''However'', because the other senshi were revived in the ''30th'' century, the Chibiusa that was born to Usagi and Mamoru never ended up traveling in time, therefore, unlike the other senshi, has no memories of her past life and has never awakened as a senshi. [[spoiler: It's because of an unconscious wish Usagi had that Chibiusa would never awaken as a senshi.]] There is one more twist to this: [[spoiler: the memories of the time-traveling Chibiusa were sealed inside the Pink Moon Crystal, so when she broke her brainwashing and started receiving her powers, she finally gained the memories of her past self]].

* ''WeBAnimation/DeathBattle'': "Goku Black Vs. Reverse Flash" gets pretty confusing after a while, because both are living temporal paradoxes who can travel in time and can't be killed permanently.

** Time travel itself seems perfectly fine: Superman went to the future and the past, the Justice League went to [=WWII=], [[Comicbook/BoosterGold one of the team is from the future]], and the list goes on. Comicbook/VandalSavage notes that his time machine couldn't send him back to a period where he already existed, [[FridgeBrilliance which may be with good reason]]: in that episode, time was falling apart only when Batman was with his very old self.

* In the rather TimeyWimeyBall finale of ''WesternAnimation/SamuraiJack'', [[spoiler: Ashi is Aku's biological daughter, and after she uses her powers to transport her and Jack into the past to kill Aku (right after Jack's past self is sent into the future) she pops out of existence because if Aku is dead then Ashi was never conceived. But if Ashi doesn't exist, then who transports Jack back in time to kill Aku?]] The OneHundredPercentCompletion ending to ''VideoGame/SamuraiJackBattleTroughTime'' would apparently retcon that [[spoiler: Ashi was able to remain intact after all, implied to be so that Jack could still travel back and stay in his own time.]]