History Main / AlternateUniverse

Given a long enough run, any series based on SuperHero [[ComicBookTropes comic books]] will [[AlternateUniverseReedRichardsIsAwesome run into these.]]

* ''VisualNovel/DanganRonpa'' has a "What if?" version where Naegi finds a switch to escape the school before any of the students can attempt a murder.

* In the season four finale of ''WesternAnimation/AdventureTime'', the BiggerBad [[spoiler: [[TheDreaded the Lich]]]] finds and opens a portal to TheMultiverse. When Finn and Jake follow, we see them in a universe where the Mushroom War never happened. Thus, Candy Kingdom doesn't exist, Jake can't talk, and Finn is not the last human. He also has a robot arm.

* Birthdayverse in ''Series/{{Angel}}''
** Illyria mentions being able to live seven different lives at once in different universes back in her days, including a universe made [[RunningGag entirely of shrimp]]. She tired of that one quickly.

* ''[[VR5 VR.5]]'''s MissingEpisode, "Parallel Lives" had Duncan wake up one morning to find himself in a universe where Sydney, rather than her sister, had died in a car crash years earlier (of course, it eventually turned out that neither sister had actually died; both the car crash and the parallel universe were [[CuckooNest complex VR hoaxes]]. The episode was intended to test the viability of replacing the central character for the second season, a possibility which became moot when the series was not renewed).
* ''WizardsOfWaverlyPlace'' had an episode where Alex goes through a mirror and enters a parallel universe where nearly everything is about her and in her favor.

[[caption-width-right:350:The criminal and the ape-thing, OK. But a ''[[{{Rule63}} woman]]''?! That's just silly.]]

** The second AU episode took place in the sixth season, where the brothers are sent to a universe [[hottip:*: which is basically our [[RealLife world]] with a bit of hyperbole]] where Supernatural [[NoticingTheFourthWall is just a TV show]] filmed in Canada, in which Sam and Dean are played by Jared Padalecki and Jensen Ackles, and there is no magic, demons, angels, monsters, or any supernatural beings at all.

* Birthdayverse in ''Series/{{Angel}}''
** Illyria mentions being able to live seven different lives at once in different universes back in her days, including a universe made entirely of shrimp. She tired of that one quickly.

** At, first, "Superstar" appears to take place in an alternate reality where Jonathan is the eponymous MartyStu, but it later turns out that '''he cast a spell that altered reality itself!'''

* The HateFic [[=/=]] FixFic [[Fanfic/MyLittleUnicorn My Little Unicorn:Magic Is Believing]] is set in one because the author hated [[WesternAnimation/MyLittlePonyFriendshipIsMagic ''[=FiM's=]'' universe]] too much to use anything from it. At least until it [[CrossOver crosses over]] with [[WesternAnimation/MyLittlePonyFriendshipIsMagic the ''[=FiM=]'' universe]] about three-quarters through. They are even merged into one kingdom at the end.

* In the KyotoAnimation adaptation of [[KeyVisualArts Key's]] VisualNovel ''VisualNovel/{{Clannad}}'', Tomoyo's arc, which was never completed properly, was showcased in an AU OVA entitled ''Another World: Tomoyo Arc'', where Tomoya never met Nagisa and Tomoyo is the winning girl.
** In July 2009, KyoAni will be releasing the final DVD of ''Clannad: ~After Story~'' that contains an extra OVA episode entitled ''Another World: Kyou Arc''. Kyou finally gets her arc!
* A major plot twist in ''RaveMaster'' involved this trope: [[spoiler: ''the entire series'' exists within an AlternateUniverse, which was created when the last survivor of the original reality manipulated time in order to create a parallel world where TheEndOfTheWorldAsWeKnowIt didn't come to pass. The OmnicidalManiac that was destroying this parallel world was in fact a balancing force created as a result of the unnatural divergence in the timestream]].
* As it was written by the same mangaka as ''Manga/RaveMaster'', ''Manga/FairyTail'' had to have one of these as well, in the form of [[BizarroUniverse Edolas]]. It makes for an interesting plot twist, and despite its relative lack of plot significance, it doesn't feel tacked on at all. Although it does explain a good few things, like Happy and Carla's origin, and why [[spoiler:Jellal and Mystogan look identical to one another]].
* ''Steel Ball Run'' is an AlternateUniverse to ''Manga/JoJosBizarreAdventure'', created ''in-continuity'' after [[spoiler: Stairway to Heaven reset the universe.]]
* The ''{{Kirby}}'' [[KirbyOfTheStars anime]] is ''meant'' to be an alternate universe from the games, something many fans miss.
** It's not just the fans--the box art for the GBA ''Kirby's Adventure'' remake ''Kirby: Nightmare in Dreamland'' inexplicably had a few anime-only characters on it.

* The HetaliaBloodbath2010 event: [[spoiler: the culprits turn out to be alternate versions of various countries from another world where everyone has cat ears and they walk around nude like it's no problem, and apparently contains ''123 different Frances.'' The survival of that world depends on finding a nation with a certain mark on their chest or butt before the end of Christmas, hence the stripping.]] ItMakesSenseInContext.
** And that's not counting the HighSchoolAU or the [[GenderBending Nyotalia-verse]] [[spoiler:which Estonia stumbles upon]].
* Unlike the traditional ''Franchise/LyricalNanoha'' setting, ''Manga/MagicalGirlLyricalNanohaINNOCENT'' is set in a universe without magic and alternate dimensions. Instead, the characters are normal humans living on earth, dueling one another via a recently introduced virtual reality-based CardBattleGame.
* In Episode 51 of ''DemashitaPowerpuffGirlsZ'', the girls spend the entire episode [[TimeTravel traveling through time]] (using the [[HumongousMecha Dyna]][[TimeMachine mo Z]]) [[MacGuffin gathering 3 flashes of light]]. Before they can get to the 2nd light, Him sends them off-course by transporting them into the universe of ''WesternAnimation/ThePowerpuffGirls'', where the PPG can be seen fighting the [[AttackOfThe50FootWhatever Giant Balloon Fish]] in Townsville. However, the girls don't stick around long enough to meet their original counterparts, as they immediately travel back to their own universe and continue time traveling.
* In the ''Anime/FullmetalAlchemist'' anime [[spoiler:the opposite side of The Gate is shown to be our universe.]] The two worlds have vastly different continuities but all humans have AlternateSelf's on the other side of the gate.

* After ''InfiniteCrisis'', the Multiverse was restored, with 52 separate realities, most of them containing the {{Elseworld}} stories. So we got to see Superman fight [[RedSon Communist Superman]] at last.

* ''The Adventures of Luther Arkwright'' is based on the premise of an infinite multiverse of parallel universes or realities which differ with each other in many things. For example, one of the main places where the action in the comic book takes place is a 20th century world where Great Britain is still ruled by a puritan government and a descendant of Oliver Cromwell. In addition, New York is New Amsterdam and the other great powers are the empires of Russia and Germany.

* Even ArchieComics do this sort of thing, a recent, notable example being the new ''Life With Archie'' series. The storyline where Archie marries Betty is treated as a different universe from where Archie marries Veronica. The former also happens to feature a character traveling between universes!
* Let's not forget how its done in their ''ComicBook/SonicTheHedgehog'', where universes are known as "Zones". Beginning with the Mirror Universe with Scourge the Hedgehog, and continuing with Blaze the Cat and her "Sol Zone". And did I mention, in one "zone", Sonic is a cop who patrols between zones?
* {{Man-Thing}}'s swamp is home to a [[{{Hellgate}} plot-friendly conflux]] of universes, including ComicBook/HowardTheDuck's home dimension.

* ''SinisterDexter'' introduced an alternate universe, which fans dubbed the [[FanNickname Doppelverse]], around the time it [[CerebusSyndrome got serious]]. The PointOfDivergence is that in the Doppelverse, the title characters were killed while still a pair of punk kids, with the result that most of their enemies are still alive and can [[BackFromTheDead come back to make trouble]].
* There are four known ones in ''PaperinikNewAdventures''. In order of appearance, they are: a universe where the [[spoiler: Evronians]] are the BenevolentPrecursors who taught science to the inhabitants of the Americas and the Vikings are the dominant power of Europe that are trying to invade (the recurring character Urk comes from there, and was accidentally pulled in Paperinik's own by the Raider); a ''LordOfTheRing''-like world conquered by an alternate and dimension-hopping [[spoiler: Raider]], who rules benevolently after finally ending the incessant wars; the timeline from which the alternate [[spoiler: Raider]] comes from (specifically an AlternateUniverse of PK's canon future); the [[spoiler: Ultimate Universe Continuity Reboot]] gets established as one by the original PK showing up in the last issue. The story ''The Day of the Cold Sun'' specifically establishes there's an infinite number of universes, but travel between them is almost impossible due the sheer numbers of them (in that story the Raider has a device to travel between them, but after finally succeeding at charging it he gets stuck in all of them at the same time because the device couldn't choose one).
* ''Comicbook/TomStrong'' features Terra Obscura, which is an alternate Earth... but it's ''not'' in another dimension or universe. It's located at the opposite end of the galaxy from "our" earth, and is its exact double -- it's even part of a replica solar system. Tom theorizes that this is a ghost particle phenomenon on a cosmic scale. What differences there are are fairly minor, with the existence of more plentiful and more powerful science-heroes on Terra Obscura chief among them. Other than that, history went along many of the exact same beats, though apparently the War of the Roses swung the other way, as New York is called "New Lancaster".

* The {{Fanfic/Uplifted}} series does this, by showing what happens when Humanity is uplifted circa 1942 by the desperate Quarians with the intention of using them to retake Rannoch.
* ''[[http://www.fanfiction.net/s/8629492/1/iSwear iSwear]]'', an {{iCarly}} fanfic, starts with Carly entering an alternate universe, and every time she loses consciousness she is automatically evicted from one universe and pushed onto another in a manner similar to ''QuantumLeap'' and ''{{Sliders}}''. The horror kicks in when you find out that [[spoiler:other versions of Carly have been doing the same thing and that many have died]] due to ending up in dangerous {{Crapsack World}}s.

* This trope is likely to be used by '''any''' IntercontinuityCrossover fanfic in which the melded continuities would otherwise contradict one another.
* ''Fanfic/WithStringsAttached'' is set on another planet in an alternate universe. Additionally, the four visit three other universes (including one set in a 1950s New York, more or less); the Fans are watching from their universe; the Dalns gods inhabit yet another universe; and Jeft comes from still another.

* [[http://www.fanfiction.net/s/7314071/1/Just_One_Big_Happy_Kingdom Just One, Big, Happy Kingdom]] is a Series/{{Merlin}} fanfic in which an eighty-year-old Merlin decides to teach his younger self a lesson by putting him in a mirror universe ("Not-Camelot") and put Not-Merlin in the normal Camelot. It's one of those mirror everybody-is-his-opposite universes.
* ''[[http://www.fanfiction.net/s/1594758/1/STRANGE_PATHS NIGHTWALKER: STRANGE PATHS]]'' is a ''{{Nightwalker}}'' fic which basically has Riho as a [[OlderThanTheyLook 140 year old vampire]] and Shido who starts out as a human detective.
* FanFic/TheOdyssey, an TabletopGame/{{Exalted}} fanfic. It's notable for both its quality and the fact that the point of divergence has not yet become apparent. [[spoiler:Something happened to the Fivescore Fellowship, though.]].
* The ''Fanfic/PonyPOVSeries'' has such a thing. It's explained that all the worlds diverged from the [[TheEarthPrimeTheory Heart World]] (implied to be the actual shows' timeline) and are effected by changes there, but can break off and continue on their own in the event the change in the Heart World is so great said universe can no longer harbor the connection. The ones the series itself focuses on are it's main timeline and the [[BadFuture Discorded Timeline]], a VillainWorld ruled by Discord, but we also see a ''lot'' of alternate timelines which Princess Luna refers to as "possibilities and impossibilities". Applejack gets to see quite a few of them on two seperate occasions, the one that means the most to her being the Orangejack universe, where she never left Manehatten. [[spoiler:She eventually gets to meet Orangejack and they team up to fight Nightmare Mirror, Applejack's own SuperpoweredEvilSide who may or may not be another alternate version of her. It also turns out Orangejack is an Element Of Generosity and there are universes were Applejack was one of the other Elements as well, all of which are summoned to fight Nightmare Mirror.]] There's also a universe were Rainbow Dash turned into Nightmare Manacle, another where Pinkie Pie turned into Nightmare Granfalloon, and another were the mane cast are the [[Series/MightyMorphinPowerRangers Mighty Morphing Power Ponies]] fighting a Goldar version of Gilda. Oh and [[spoiler:Pinkie Pie is actually the G3.5 Pinkie Pie and is how she is thanks to being left pretty much untouched by a CosmicRetcon that turned that universe into the G4 universe.]]

* Certain ''Franchise/PowerRangers''/''Franchise/SuperSentai'' crossovers treat both series as alternate universes to each other - fitting, considering that one lends source material to the other. This is especially noticeable in stories where a PR team is placed opposite the Sentai team that served as its source, for example, [[http://www.fanfiction.net/s/2889432/1/Magiranger-vs-Mystic-Force this]] ''Series/PowerRangersMysticForce''/''Series/MahouSentaiMagiranger'' story.
* Fanfic/DeathsChild: Lily Potter is Death's one day of mortality ... Which changes everything.
* Fanfic/AgentLokiInternationalManOfMayhem takes an alternate route from the ending of Film/TheAvengers to continue with Loki being used as a TokenEvilTeammate by SHIELD.
* The HateFic / FixFic [[Fanfic/MyLittleUnicorn My Little Unicorn:Magic Is Believing]] is set in one because the author hated [[WesternAnimation/MyLittlePonyFriendshipIsMagic ''[=FiM's=]'' universe]] too much to use anything from it. At least until it [[CrossOver crosses over]] with [[WesternAnimation/MyLittlePonyFriendshipIsMagic the ''[=FiM=]'' universe]] about three-quarters through. They are even merged into one kingdom at the end.

* It's implied that the two ''Disney/{{Cinderella}}'' sequels are set in different universes.

* Creator/RobertAHeinlein's ''Literature/TheNumberOfTheBeast'' and ''Literature/TheCatWhoWalksThroughWalls'' are based on this, exploring various fictional universes created not only by Heinlein but also others, especially [[Literature/LandOfOz Oz]].
* This is the origin of all the strange things in JohnDiesAtTheEnd.
* The alternate history series ''Literature/SixteenThirtyTwo'' runs on this trope. Not long after the Virginia mining town from 2000 appears in Europe in 1632 during the Thirty Years War, some characters speculate they have moved to a different universe.

* The ''Myriad Universes'' ''Franchise/StarTrek'' novella collections have the "for want of a nail" version of this trope. The Mirror Universe short story collections, on the other hand, are ''very'' different to the main universe.
* ''Literature/TheManInTheHighCastle'' by Creator/PhilipKDick contains an alternate 1960s California controlled by the Japanese after a defeat of the allies during WWII. There is mention of another alternate reality, apparently revealed to an author who writes a book about such an alternate in which the US does not lose WWII. This is slowly revealed not to be "our" alternate, but one dreamed up by the writer, and of no special significance. The book was written using the I-Ching as a guide to the character's actions.

* Creator/MichaelKurland has a few examples involving world-hopping, including ''Literature/TheUnicornGirl'' and ''The Whenabouts Of Burr''.
* ''The Devil's Alphabet'' by Daryl Gregory is a novel where a virus of sorts mutates the populations of a couple of cities in different parts of the world. The eventual realization is that the various types of new humans (Argos, Betas and Charlies) are what humans are normally like in alternate versions of the world.

* ''Series/DarkShadows'' may well have brought this trope to television for the first time.

* "Ace" Rimmer (what a guy!) on ''Series/RedDwarf'' came from an AlternateUniverse, and travelled between dimensions. The Red Dwarf crew themselves had previously travelled into an Alternate Universe in the episode "Parallel Universe". Some episodes have featured similar alternate versions of characters and events, but were a result of time travel rather than passing into another Universe (notably "Timeslides" and "Inquisitor").
** The books delve into this too. While multiple universes are established in ''Better Than Life'', they really come into play in ''Last Human'' and ''Backwards''. ''Last Human'' occurs when the crew return from Backwards Earth to the wrong universe and try to track down Lister's other self. In ''Backwards'', Ace Rimmer is given a backstory behind Project: Wildfire and turns up to save the crew. Bonus points for the fact that both books, having each been written by Grant and Naylor separately, take place in alternate universes to each other.

* ''Series/StarTrekVoyager'' didn't make use of the MirrorUniverse, but in "Living Witness", a historian hundreds of years in Voyager's future has created a "historically accurate" holo-program depicting the crew as murderous thugs who started a war on his planet. It's up to the Emergency Medical Hologram (the only surviving witness) to put things right... which isn't easy, as he's being portrayed as a MadDoctor. ''Series/StarTrekTheNextGeneration'' also didn't have the mirror universe, although it did have alternate universe stories (as the term "mirror universe" in ''Star Trek'' refers specifically to that featured in ''[[Series/StarTrekTheOriginalSeries The Original Series]]'' and ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'').

* "Parallels" in ''Series/StarTrekTheNextGeneration'' -- "I do remember. I just remember it differently."

* ''{{Smallville}}'' had an interesting subversion: Clark [[CuckooNest wakes up in a mental asylum]]; apparently, he started having delusions of superdom in high school, and his "saving" of Lex in the first episode actually cost Lex his legs. Oh, and Chloe is a freaking nutcase. Of course, it was all a delusion caused by an escaped Phantom that attacked him in his barn and invaded his mind. John Jones (the Martian Manhunter) helped him escape by entering the illusion (as another inmate), and capturing the creature in a Kryptonian crystal.
** ''Noir'': JimmyOlsen wakes up in a FilmNoir universe.
** Season 10 had an AlternateUniverse as a major plot line, Clark discovers a kryptonian artifact called a "mirror box" and when activated it takes him to world where the Kents never adopted him, instead he was raised by Lionel and goes by the name "Clark Luthor". Clark Luthor himself is brought to Clark Kent's world and causes no end of trouble before the original Clark manages to switch them back. Then it turns out the alternate Lionel managed to come through to the main world with Clark, taking the place of the original Lionel (who was dead) with a story that he'd faked his death. Then Clark Luthor uses ''his'' mirror box to come back and send our Clark to his world, where he helps the alternate Jonathan reconnect with Martha, and convinces Clark Luthor to try and use his powers for good, rather than live in Lionel's shadow.
* In ''{{Seinfeld}}'' episode #137 "The Bizarro Jerry", Elaine is in a similar social circle where the Kramer equivalent is neat, George's is responsible, etc.
* In ''Series/{{NCIS}}'', a generally reality based show, features a series of clips from AlternateUniverse based on a series of What-If moments. What if Kate hadn't died? [[spoiler: Tony and Kate get married and have a kid. Yay! Ziva goes from crazy assassin to even crazier assassin. Aww.]] What if Gibbs also hadn't killed Pedro Hernandez? [[spoiler: His demons consume him, he quits NCIS sooner, he becomes a (likely) alchoholic, shuts himself in his basement for months, ''[[FelonyMisdemeanor is rude to Abby]]'', [[ArsonMurderAndJaywalking and Abby/McGee and Tony/Kate become canon.]]]] What if Shannon and Kelly hadn't died? (Warning: ''major'' TearJerker behind those spoilers. [[spoiler: [[TearJerker Gibbs dies fighting overseas. No matter what, he lost his family.]]]]
** Parent series ''Series/{{JAG}}'' also had an {{Elseworld}} episode, appropriately named "WhatIf".
* ''Series/StargateSG1'' has had many different alternate universes. Oftentimes, the "alternate" Samantha Carter is not in the military and is engaged/married to the "alternate" Jack O'Neill. Alternately Daniel Jackson was never part of the Stargate Program. More often or not, when this is used, Earth is under imminent Goa'uld attack.
** ''Atlantis'' also does this, though the details vary, and the universes aren't ''usually'' quite the CrapsackWorld versions that ''SG-1'' is fond of.
*** In the one in the episode ''[=McKay=] and Mrs. Miller'', Rodney is a really nice guy with lots of friends and Sheppard is a member of Mensa, greatly annoying everyone with his egoism. In our universe, Rodney is the egoist one, Sheppard is a nice guy who took a Mensa test but turned down the offer to join.
*** And another is shown in the penultimate episode ''Vegas''. There, Sheppard is a homicide detective with massive gambling debts. He couldn't be included in the team because the stunt he pulled off in Afghanistan got him dishonorably discharged instead of getting ReassignedToAntarctica in time for the pilot. Rodney is more likeable (though one scene suggests that he's simply better at keeping a lid on his ego) and the Wraith already made an attempt at culling Earth just to be repelled by the control chair in Area 51. Oh, and Todd got so delirious from starvation he's speaking in rhymes.
*** The Rodney from ''Vegas'' also mentioned that he once traveled to yet another universe and met an alternate Sheppard who was similar to the main Sheppard.

* A slightly different take on this was done in "Author Author" in ''Series/StarTrekVoyager'', in which the Doctor created a holodeck program peopled by altered versions of the Voyager crew.
* ''Series/DoctorWho'':
** "Inferno" an alternate totalitarian Britain (branching off with the 'defence of the republic act, 1943'), which is in a still greater rush to get free power from tapping the magma of the Earth. It is destroyed, with the Doctor able to just avert the similar events happening a few hours later in his 'home' alternate. Not bad at all.
** "Rise of the Cybermen"/"Age of Steel" has the TARDIS fall through a crack in time and land in a universe where the Cybermen were being created on Earth. Mickey explicitly references how common the trope is in [[ComicBookTropes comics]]. This universe crossed over again in "Army of Ghosts"/"Doomsday" and its effects continued to be felt in ''Series/{{Torchwood}}'''s "Cyberwoman" episode. And in the finale of Series 4 of ''Doctor Who''.
** In "Turn Left", Donna Noble has an entire alternate universe built around her, where she never met the Doctor, and he consequently dies after the events of "The Runaway Bride." It does not fare well. In fact, the universe without the Doctor is pretty much a terrible place to be.
* Sci-fi series ''{{Lexx}}'' made this its staple. The first season of the show involved the characters jumping through an inter-universe rift twice, and in the second season once at the beginning, before the entire Light Zone was wiped out in the second SeasonFinale, forcing the Lexx (and a large amount of particle matter from the zone) to get forced back out into the other universe.
* Homaged in ''Series/MysteryScienceTheater3000'', "Last of the Wild Horses", where Dr. Forester and TV's Frank get to quip at the movie, and evil Mike and Bots watch on from Deep 13.
* An AlternateUniverse seems to be seen in the ''Series/{{Supernatural}}'' episode "What Is And What Should Never Be", but it's really all in Dean's head and everything is his perception -- Mary's perfect, Sam and Dean are a bit wussy and the family is like any other. In his fantasy, his mother Mary and Sam's girlfriend Jessica were never killed by Azazel, so the Winchester family live perfectly normal lives and his Dad died peacefully. As Dean is utterly unhappy there, it seems he wants a extremely codependent relationship with Sam and the wracking memories of his family.
** A real AlternateUniverse, or rather a series of them, pops up in the episode "Mystery Spot" thanks to a [[GroundhogDayLoop repeating time loop]] in which Dean keeps dying. The iteration before the final time loop lasts months instead of the standard day, resulting in a dark, isolated Sam.
** Later in the episode "It's a Terrible Life", where Dean is a Marketing Director for a firm and Sam is a techie in the same building with no memory of their hunter life beforehand apart from a few dreams, it's revealed that this was all [[SecretTestOfCharacter a ruse from an angel]] to show Dean hunting is in his blood and he will always find a way to be a hunter. This is also a play on the WonderfulLife trope.
** The second AU episode took place in the sixth season, where the brothers are sent to a universe [[hottip:*: which is basically our [[RealLife world]] with a bit of hyperbole]] where Supernatural [[NoticingTheFourthWall is just a TV show]] filmed in Canada, in which Sam and Dean are played by Jared Padalecki and Jensen Ackles, and there is no magic, demons, angels, monsters, or any supernatural beings at all.
** And then there's "My Heart Will Go On", in which the Titanic never sank, somehow causing the Winchesters to own a Mustang, Bobby to be married, and Celine Dion to be a lounge singer in Quebec.
* ''KamenRiderDecade'' uses Alternate Universes for its main premise. The main cast travels through various alternate universes which are modified versions of the previous Kamen Rider shows.
* ''KamenRiderDragonKnight'' uses the concept of alternate universes, accessible through mirrors. The Earth Kamen Riders are chosen because they are genetic doubles of the original Kamen Riders from the alternate universe of Ventara.
* Season 6 of ''Series/{{Lost}}'' features an alternate universe where 815 never crashed, and many other details are different. WordOfGod has it that neither timeline should be called "alternate" or "parallel" as those words imply that one is more real than the other. [[InsistentTerminology Flash-sideways]] has been decided to be the proper term. People in the flash-sideways actually retain memories from the other timeline, with [[BadAss Desmond]] seemingly able to switch between both willingly. [[spoiler:[[DeadAllAlong The finale blows the flash-sideways out of the water entirely.]]]]
* The Alternate Universe on ''Series/{{Fringe}}'' is a world where pockets of time and space become unstable due to [[spoiler: Walter's kidnapping of Peter by crossing to the other side]].
** In the AU, there are many details that differ from the characters' home universe, such as Martin Luther King Jr. being on the American $20 bill and the World Trade Centers still standing and [[spoiler: Walter never went insane (and never hard parts of his brain removed), and is now the Secretary of Defense and head of their Fringe team, which takes far more drastic action to combat the far more drastic "Fringe Events" that occur "over there".]] Also, they're keen to show the presence of [[ZeppelinsFromAnotherWorld zeppelins]], just so you know it's an alternate universe.

* The ''Series/{{Community}}'' episode "Remedial Chaos Theory" features the group rolling a die to choose who will go to the door to get the pizza. [[GenreSavvy Abed]] warns that this will create 6 (actually 7) alternate universes. Everyone else of course dismisses this, but we the audience get to watch each one unfold. The differences ranges from different characters hooking up, mental break downs occurring, everyone having an awesome night, and ''everything going to shit''.

* ''TabletopGame/{{TORG}}'' features several different dimensions/realities, each corresponding to a different genre (such as Aysle, a traditional world of MedievalEuropeanFantasy; the Cyberpapacy, a CyberPunk world run by a CorruptChurch; the SpaceOpera-influenced dimension of the Space Gods; Orrorsh, a Lovecraftian CosmicHorrorStory in a ''Heart of Darkness'' style British colonial jungle setting; the Nile Empire, a world of Pulp Action Adventure; the Living Land, with sentient dinosaurs; and others), all cooperating to invade Earth.
** Part of what made ''TORG'' such an interesting game is that it was based on distinctly different rules for how reality worked, depending on the context of the home dimension. The Nile Empire, for example, had no room for moral ambiguities: every character was either Good or Evil, though they could change from one to the other under the right circumstances. Characters could engage in literal 'reality duels' with opponents from different dimensions, and the [[BigBad High Lords]] could do the same with entire areas of real estate.
* The ''TabletopGame/{{GURPS}} InfiniteWorlds'' setting involves the [[PlayerCharacters PCs]] as agents travelling through alternate universes. Officially ''all'' GURPS settings are universes within the ''Infinite Worlds''. This includes assorted [[AlternateHistory Alternate Histories]] (''GURPS [[{{Magitek}} Technomancer]]'', ''GURPSReignOfSteel''), several universes where AllMythsAreTrue (''GURPS [[KingArthur Camelot]]'', ''GURPS {{Atlantis}}''), multiple worlds with superheroes (''GURPSSupers'', ''GURPS International Super Teams''), and even universes inexplicably modeled on the popular fiction of the baseline universe (''GURPS [[ConanTheBarbarian Conan]]'', ''GURPS Literature/{{Discworld}}'')!
** The enemy timeline in ''Infinite Worlds'' is Centrum, a scientific state that wants what is best for all, and for this to continue (discovering [[TheHouseOfPlantagenet where this one branched off]] is a surprise)... others in the ''Alternate Worlds'' books have included Gernsback (named for the Golden Age SF editor), where Nikola Tesla's inventions shaped the development of science; Excalli, where the dominant empire is an Aztec-derived one; Roma Aeterna, where the Empire of Rome simply carried on, with the adoption of science; an alternate where China continued to trade overseas; and several versions of the usual "Nazis triumphant" parallel. Oh, and the United States of Lizardia, where dinosaurs evolved into sentient beings but somehow ended up recapitulating human history along the way.

* The ''SuperRobotWars'' games are set in an Alternate universes for each of the series portrayed in it(the alternate, of course, being that they're all happening at the same time in the same place). Each game or series is, additionally, an alternate universe from each other. Then there is the Original Generation universe, which contains all the original characters and mecha from the other games and then some, which also has its own MirrorUniverse, the Shadow-Mirror universe, which is itself the Original Generation version of the Shadow-Mirror universe from ''SuperRobotWarsAdvance''. Confused yet? We haven't even gotten to the ''VideoGame/EndlessFrontier''!
** In ''VideoGame/SuperRobotWarsL'', ''MacrossFrontier'', ''VoltesV'', and ''IczerOne'' all come from one universe and end up somehow Folding into another, which is where all the other series take place.
* Nearly every character from ''KingdomHearts'' is an alternate version of his/her Disney or Final Fantasy counterpart (otherwise the game would run into some ''serious'' continuity problems). This is implicitly stated in the ''{{Tron}}'' world.
* The two ''SonicRush'' games feature a parallel universe. The first game takes place in Sonic's universe, which is slowly merging with Blaze's. The second game takes place in Blaze's universe... which is apparently a giant ocean.
* ''Kirby and the Amazing Mirror'' takes place in another literal mirror universe (akin to the ''Charmed'' and ''Red Dwarf'' ones above), parallel to Dreamland and containing mirror versions of Meta Knight and Kirby.

* ''VideoGame/TheWorldEndsWithYou'' has ''Another Day''. This takes place in a world where Neku and his friends [[spoiler: never died]], Shuto is TheHero with Neku as TheLancer, Tin Pin Slammer is SeriousBusiness, Eri's parents decided to call her Shiki for some reason, and [[ArsonMurderAndJaywalking Neku is less emo]].
** And, mind-bogglingly, despite what the game says, it actually has some bearing on the main plot. [[spoiler:Joshua]] flees to that universe after [[spoiler:shielding Neku from Minamimoto's Lv. ''i'' Flare]]. Whereupon he challenges Another Day!Neku to a BossRush to kill time.
** It also seems to cross over into ''TheMultiverse'' with certain people as they can go to other dimensions, and even meet themselves if they aren't careful.
* The ''VideoGame/{{Resistance}}'' games take place in a setting where after WorldWarI Germany's economy wasn't totally devastated, therefore AdolfHitler never rises to power and there was no WorldWarII. Instead, creatures known as Chimera take over the entirety of Europe and by the sequel have wiped out the US.
* Based on what has thus far been fan-translated of ''MagicalGirlLyricalNanoha A's: The Battle of Aces'', it takes place in an AU where [[spoiler: Reinforce I/Eins survives and the corrupted Book of Darkness creates "Dark Pieces" of selected cast members ([[DemotedToExtra sorry, Arf and Yuuno]]) to get its own back again.]]

* The DLC for ''VideoGame/DragonAgeOrigins'' entitled ''The Darkspawn Chronicles'' pitches the idea of a world where TheHero died near the beginning of the game, thus leaving [[TheWoobie Alistair]] to save the day. [[spoiler:It does not end well.]]
* In the second installment of the "Timeline" mod trilogy for ''VideoGame/{{Half-Life}}'', Gordon Freeman is transported to a parallel Earth where the US never rebelled (the major superpowers are the British Empire, the Soviets and the Japanese), and an ice age began some 300 years earlier, threatening human survival. That world's Gordon Freeman has failed, so our world's equivalent is sent to stop the Xen invasion there (as well as an invasion of time-travelling Nazis from our dimension).
* The original ''CrazyTaxi'' has "Another Day" mode. Where in the normal mode most customers want to travel in a certain direction which leads to the cabbie going in a counter-clockwise direction around the circuit, in "Another Day", the customers usually want to travel to a destination in the opposite direction, causing the cabbie to go in a clockwise direction around the circuit.
* The areas Yaschas Massif and Academia in VideoGame/{{FinalFantasyXIII-2}} have alternate versions that appear after solving paradoxes in the timeline, and are marked with an X in the year name (ex. 01X AF). You can still go back to the original universe, though.

* The Distortion World in ''[[VideoGame/PokemonDiamondAndPearl Pokemon Platinum]]'' is one of these.
** ''[[VideoGame/PokemonBlackAndWhite Pokémon Black and White]]'' establishes the reason for having OneGameForThePriceOfTwo as because of this trope- the other version is in fact a parallel universe to the one you're playing, and the histories of a few areas and characters are different. Using the Entralink you can visit the other world and see the changes.

* The ''[[VideoGame/TotalWar Medieval II: Total War]]'' conversion mod ''{{Thera}}'' is a funny example. Thera vaguely resembles high-medieval Earth as far as climate, positions of civilizations and the cultural, technological and historical themes of said civilizations are concerned. Several real-world religions such as Christianity, Islam and NorseMythology are present as well. That said, the world has a radically different history, and the landmasses are different. Also, there are a number of LowFantasy elements present, especially in Version 4 of the mod: velociraptor-riding [[{{Mayincatec}} Paynal]] cavalry, a playable faction being a [[{{Expy}} dead-ringer]] for [[Literature/TheLordOfTheRings Isengard]], hostile tribes of frost giants roaming around the northernmost continent, and various {{Public Domain Artifact}}s such as Excalibur, the Holy Grail and the Book of Morrigan being real and possessing magical power.
* Makoto's Story "Slight Hope" in ''VideoGame/BlazBlueContinuumShift'' has her accidentally travelled to an alternate history world whereby Noel wasn't alive and it took place 3 days prior to her own timeline. Rachel ultimately explained this to Makoto and guided her back to her own timeline. Even in Litchi's story, she could sense an alternate universe happening.

* Every path in the multi-route ''[[{{Nasuverse}} TYPE-MOON]]'' games is a potential outcome of the main scenario, which makes it rather difficult to establish [[{{Canon}} the rules of the 'verse]] due to the plot differences in each route; according to WordOfGod, [[TheMultiverse all of them are canon]].
* The main plot behind ''VisualNovel/LittleBusters'' can be described as this. [[spoiler:At first you don't realize because you're playing like any other DSIM, but at each playthrough the two main characters evolve a little (better seen on their status screens) and little things change from one playthrough to the other. It's only when you complete the Rin route for the second time, after playing through all the other five routes that it's revealed that the world they live in is actually an alternate universe created for the two main characters by the other eight, in order to help them cope with what happened in the real world.]]

* In ''Webcomic/ElGoonishShive'', the WordOfGod said that at least four [[AnotherDimension dimensions]] have meddled with the "main" one. Most of them are {{Alternate Universe}}s, each with its own version of Tedd or other main characters.
* ''SupernormalStep'' takes place on an AU Earth with magic and fantasy creatures. It is one of [[MultiVerse many dimensions]], and two of the main characters are actually from our normal, boring one.

* MinionsAtWork: Invoked [[http://www.minionsatwork.com/2009/01/bonus-minions-147-alternator-problem.html here]].

* In ''WhatBirdsKnow'', a mysterious tower acts as a gateway between the normal world and a bizarre version where people lay eggs, among other oddities.

* ''BittersweetCandyBowl'', According to the commentary, the chapter "[[http://www.bittersweetcandybowl.com/c59/p1.html Another Path]]" was originally intended to be set in an alternate universe where [[spoiler:Paulo had sex with Lucy during her [[HeroicBSOD Mental Breakdown]] in "Another Shoulder"]]. The final version has it as a daydream of Paulo's.

* In ''Dragon City'', Erin's friend Natasha reveals herself to an alternate universe counterpart despite Erin having blue scales and Natasha having brown.
** Actually, as Natasha (the brown Erin) points out, due to genetics, Erin was more likely to be brown than blue and that the blue Erin is a genetic fluke.
** Yes, Erin IS that vain to have made friends with her other world counterpart.
* [[http://www.vexxarr.com/archive.php?seldate=052807 Very briefly done]] in {{vexxarr}}.

* ''DumbingOfAge'' is an alternate universe to ''Webcomic/{{Shortpacked}}'' and the other series in Dave Willis' Webcomic/WalkyVerse. It reboots the story by placing it back in college (most of the Walky cast graduated from college in 2001) removing the science fiction elements completely, and using a SlidingTimescale so the characters will never graduate. Shortpacked is still running alongside it, though, ensuring the walkyverse will continue.
* In ''{{Bobwhite}}'', [[http://www.bobwhitecomics.com/?webcomic_post=20090407 Cleo freaks out]] over the many-worlds hypothesis and its implications on fast food. In this universe, she never orders burritos because they're gross... which means that in some other universe she ''always'' orders burritos. ''But why?''
* In ''Webcomic/{{Homestuck}}'', initiating [[spoiler: the Scratch]] creates one of these by [[ResetButton resetting the conditions of the game]], including the players and their universe. [[spoiler: As a result, the players of the initial session switch places with their ectobiological parents, and vice-versa.]] This has happened twice so far: once to Earth, and once to [[spoiler: Alternia]].
* Webcomic/{{Parallels}}
-->''Keeping the spaceways safe one universe at a time.''
* ''Webcomic/MSPaintMasterpieces'' has a number of alternate timelines that are shown as side-stories. [[spoiler: As X explains in filler, there's only one ''actual'' timeline, and when you mess with time travel, you destroy the projected one, which is what Wily's up to between the first and second games.]]
* The protagonists of ''Webcomic/PaoniaPawns'' gain the ability to travel between these; in many, some sort of [[ApocalypseHow disaster]] has wrecked the local civilization.
* If they can be successfully opened, Panegates in ''Webcomic/TheMansionOfE'' allow access to alternate universes.

* ''{{Tasakeru}}'' takes place in an alternate universe where humans have never existed.
* ''SurvivalOfTheFittest'' has had several small-scale [=AU=] [=RPs=]. These range from simple 'What-If' scenarios (What If the students had been rescued on Day 3, What If ''[=SOTF=]'' really ''was'' a TV show, etc) to radically different concepts such as [[HumongousMecha Mech]] ''[=SOTF=]'' and ''[=SOTF=]'' with zombies.
** Fairly recently, a spin-off site effectively dedicated to AlternateUniverse versions of ''SurvivalOfTheFittest'' was created, with the pilot in an interesting ContinuityNod, being an alternate version of ''Literature/BattleRoyale'', the concept which [=SotF=] was based off.
*** The Mini site also now hosts ''SOTF: Evolution'', which is like normal SOTF, only with 20 characters instead of the LoadsAndLoadsOfCharacters the main site has, and with SuperSerum induced mutations instead of designated weapons.

* A popular fad on {{YTMND}} is to take pre-existing memes and create AlternateUniverse counterparts, usually under the PTKFGS moniker ("Punch The Keys, For God's Sake!", another one of SeanConnery's lines from the famous scene in ''FindingForrester'' that named the website), although even more AlternateUniverse versions exist, usually as either "Yes Yes" or the elusive "Fourth Corner", where no-one can really agree on a final name for the latter.

* Come on, we have to mention JennyEverywhere in here somehow! (She is meant to exist in all possible such universes and can shift between them. Conveniently allowing for [[DependingOnTheAuthor variability in settings and variations on the nature of the character in different stories.]])

* In the ''CodenameKidsNextDoor'' episode "Operation: P.O.O.L." Numbah Four travelled to an alternate world where the KND were the DNK (Destructively Nefarious Kids). His own evil counterpart was the leader (complete with goatee).
* In the season four finale of ''WesternAnimation/AdventureTime'', the BiggerBad [[spoiler: [[TheDreaded the Lich]]]] finds and opens a portal to TheMultiverse. When Finn and Jake follow, we see them in a universe where the Mushroom War never happened. Thus, Candy Kingdom doesn't exist, Jake can't talk, and Finn is not the last human. He also has a robot arm.
** We find out more about this in the season 5 premiere. [[spoiler: Finn wished the Lich out of existence, so he and Jake ended up in an alternate timeline where the Ice King performed a HeroicSacrifice to prevent the final bomb from falling in the Mushroom War, and the creation of the Lich, from ever happening.]]

* Very briefly done in {{vexxarr}}.

* Creator/RobertAHeinlein's ''Literature/TheNumberOfTheBeast'' and ''Literature/TheCatWhoWalkedThroughWalls'' are based on this, exploring various fictional universes created not only by Heinlein but also others, especially [[Literature/LandOfOz Oz]].

* The alternate history series ''1632'' runs on this trope. Not long after the Virginia mining town from 2000 appears in Europe in 1632 during the Thirty Years War, some characters speculate they have moved to a different universe.

* ''TORG'' features several different dimensions/realities, each corresponding to a different genre (such as Aysle, a traditional world of MedievalEuropeanFantasy; the Cyberpapacy, a CyberPunk world run by a CorruptChurch; the SpaceOpera-influenced dimension of the Space Gods; Orrorsh, a Lovecraftian CosmicHorrorStory in a ''Heart of Darkness'' style British colonial jungle setting; the Nile Empire, a world of Pulp Action Adventure; the Living Land, with sentient dinosaurs; and others), all cooperating to invade Earth.

* The two ''Sonic Rush'' games feature a parallel universe. The first game takes place in Sonic's universe, which is slowly merging with Blaze's. The second game takes place in Blaze's universe... which is apparently a giant ocean.

* The original ''Crazy Taxi'' has "Another Day" mode. Where in the normal mode most customers want to travel in a certain direction which leads to the cabbie going in a counter-clockwise direction around the circuit, in "Another Day", the customers usually want to travel to a destination in the opposite direction, causing the cabbie to go in a clockwise direction around the circuit.

* In ''Webcomic/DrMcNinja'' The universe the setting is in is sandwiched between two other realities, the Radical land, and what amounts to the real world. These universes both bleed their coolness and lameness into the comics one respectively so that its cooler than our universe but not as cool as the radical lands.

* [[http://www.drunkduck.com/Jix Jix]] had a story that took place in an alternate reality where Remula had taken over the Earth and it was discovered later that the original Lauren had actually be transported to that universe when she caught up to her counterpart.

* Very briefly done in [[http://www.vexxarr.com/archive.php?seldate=052807 vexxarr]].

* ''Dumbing of Age'' is an alternate universe to ''Webcomic/{{Shortpacked}}'' and the other series in Dave Willis' Webcomic/WalkyVerse. It reboots the story by placing it back in college (most of the Walky cast graduated from college in 2001) removing the science fiction elements completely, and using a SlidingTimescale so the characters will never graduate. Shortpacked is still running alongside it, though, ensuring the walkyverse will continue.

* ''Dumbing of Age'' is an alternate universe to ''Webcomic/{{Shortpacked}}'' and the other series in Dave Willis' WalkyVerse. It reboots the story by placing it back in college (most of the Walky cast graduated from college in 2001) removing the science fiction elements completely, and using a SlidingTimescale so the characters will never graduate. Shortpacked is still running alongside it, though, ensuring the walkyverse will continue.

* Come on, we have to mention JennyEverywhere in here somehow! (She is meant to exist in all possible such universes and can shift between them.)

* Makoto's Story "Slight Hope" in [[BlazblueContinuumShift Blazblue Continuum Shift]] has her accidentally travelled to an alternate history world whereby Noel wasn't alive and it took place 3 days prior to her own timeline. Rachel ultimately explained this to Makoto and guided her back to her own timeline. Even in Litchi's story, she could sense an alternate universe happening.

* The ''Franchise/WhenTheyCry''-franchise is filled of this, refered to as fragments/kakera. In [[VisualNovel/HigurashiNoNakuKoroNi Higurashi]] the GroundHogDay is revealed not to be repeats of the same events but instead different universes with a certain person pushing the ResetButton after each arc searching for a fragment in the sea of fragments where [[spoiler: Rika won't be killed]]. In [[VisualNovel/UminekoNoNakuKoroNi Umineko]] we are introduced to witches who can travel in the sea of fragments looking for specifik events that fit their needs or wants.

* ''VisualNovel/UminekoNoNakuKoroNi'' is filled with these. Between worlds, there is a massive empty space where all possible alternate worlds can be found. Bernkastel's "Magic of Miracles" is 'merely' being able to find the alternate world where whatever she wants to happen happens. Note this allows her to cause absolutely anything to happen, so long as the probability of the even isn't absolute zero. [[RealityWarper It's a very scary power.]]

* ''[[http://www.fanfiction.net/s/1594758/1/STRANGE_PATHS NIGHTWALKER: STRANGE PATHS]]'' is a ''{{Nightwalker}}'' fic which basically has Riho as a [[OlderThanTheyLook 300 or so year old vampire]] and Shido who starts out as a human detective.

A story in which the characters we know are seen in a reality that's somehow different, often disturbingly so. If they can access multiple alternative realities, that's TheMultiverse.

Sometimes everyone has an EvilTwin. Other times, everyone has a twin that's just a little different. Allows the goodies to be baddies for an episode, or for half of the cast to be killed -- but [[AllTheMyriadWays not really]]. Sometimes it's just part of SideStoryBonusArt.

If the writers want to depict an AlternateUniverse, but the show's genre would not usually allow an AlternateUniverse ''per se'', the depiction may be accomplished via an extended DreamSequence.

** InSpiteOfANail -- Tiny changes have made the world almost the same but the differences are critical (or wildly different, but the cast is still the same and still together.)

* {{Elseworld}} -- Famous character placed into a situation which potentially is wildly different.
* WonderfulLife -- You get to see how the world would have turned out if you were never born.

* FanFic/TheOdyssey, an TabletopGame/{{Exalted}} fanfic. It's notable for both its quality and the fact that the point of divergence has not yet become apparent. [[spoiler:Something happened to the Fivescore Fellowship, though.]]).

** We find out more about this in the season 5 premiere. [[spoiler: Finn wished the Lich out of existence, so he and Jake ended up in an alternate timeline where the Ice King performed a HeroicSacrifice to prevent the Mushroom War, and the creation of the Lich, from ever happening.]]