Cryptic Background Reference

aka: Whats A Secret Four

"Part of the attraction of The Lord of the Rings is, I think, due to the glimpses of a large history in the background: an attraction like that of viewing far off an unvisited island, or seeing the towers of a distant city gleaming in a sunlit mist. To go there is to destroy the magic, unless new unattainable vistas are again revealed."

— J. R. R. Tolkien

One way of building background is to have the characters refer to things without explaining exactly what those things are. The slight confusion caused is balanced by the sense given of a larger world, outside the plot. If a story is extended to a long enough series (especially when there's a high turnover of writers), most of these cryptic references will eventually be explained and/or used as Canon Fodder, but often one or two will still never appear in story. What such references really mean are a favorite subject for fan discussions and a breeding ground for various theories. The rise of the web, and later social media, has somewhat reduced the incidence of such things, as it has become easier to just ask the creators what something means; they'll probably answer it if doing so won't spoil future plot developments. Of course, this hasn't totally eliminated them, as there are some things that the creators just don't care enough about to answer or think is better left to fan interpretation.

Compare to the closely-related Noodle Incident which is specifically for the incident in question being too embarrassing and ridiculous to elaborate. See also Canon Fodder, Narrative Filigree, What Happened to the Mouse? and Mysterious Past. Unknown Character, Great Offscreen War and Cataclysm Backstory are commonly played as sub-tropes of this, as is Famous, Famous, Fictional. See Hufflepuff House for organizations with this treatment more referred to than seen. If the reference in question is actually explained later on, it becomes Foreshadowing, Chekhov's Gun, or Brick Joke. If not, it becomes a Noodle Incident. When played for laughs or for horror, it overlaps with Nothing Is Funnier (and sometimes Funny Background Event) or Nothing Is Scarier. Interestingly, if you start following a long-running series from the middle (rather than from the start), every Continuity Nod in it effectively becomes a Cryptic Background Reference for you, so it's all just a matter of perspective, really.

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Example subpages:

• Anime & Manga
• Literature
• Live-Action TV
• Video Games

Other examples:

Comic Books

• Astro City uses this trope a lot, especially in the earlier volumes when the universe wasn't so fleshed out. There are constant references to heroes, villains, and incidents that the readers have not seen yet - and sometimes never see, since the story is more about how people think and live in a superhero world than about the actual exploits of the heroes. The author, Kurt Busiek, uses this trope a lot in his work - the same treatment is given to his magic-replaced-technology World War I story Arrowsmith, among others.
• ElfQuest used to do this, but over the years, people Running the Asylum have started to fill in most of the gaps. Whether they should have bothered or not is a matter of some debate.
• The League of Extraordinary Gentlemen does this constantly to fill in the gaps between the novels that the characters first appeared in and the actual LoEG comics themselves. To the point where a reference guide for all of the bits in the first collected comic was three times the thickness of the comic itself. One panel could have two pages worth of 'This is the X from Y', especially in the League’s museum base.
• This pops up in another work by Alan Moore, Promethea. There are several references to adversaries and events from Promethea's past that are never seen or elaborated upon. The Shadow Queen however is probably the most notable since she is referred to several times without any details about her nature or ambitions revealed to the audience.
• A Republic comic showed a Geonosian hive on the ice world Zaadja where several Mandalorian corpses were embedded into the walls. At the time of writing both races had an alliance with the Confederacy which would rule out any logical reason.
• Writer Tristan Huw Jones would pepper his Tales of the TMNT stories with these, particularly when it came to characters.
• James Robert's Transformers stories (The Transformers: Last Stand of the Wreckers, The Transformers: More than Meets the Eye...) tend to mention things, events, and places that are often very slowly elaborated upon or explained over time, if at all.
• New Avengers (2015): During issue 6, the Avengers of the future mention the "Eternity Wars", which had some part to play in Hulkling becoming what they proclaim "King of Space", before adding that it's apparently some time away. Then Collapsar hurriedly asks Sunspot to forget he ever heard anything. The follow-up series U.S.Avengers mentions it again, with the future Captain America saying only that it was "worse" than Zero Day, when pretty much every major hero died at Thanos's hands.
• Disney Ducks Comic Universe: Scrooge McDuck made many oblique references in comics by Carl Barks, which were intended as pure throwaway references to give the impression that Scrooge has lived a long, exciting life as an adventurer and businessman. Many years later, Don Rosa took many of Barks's offhand references and used them as the basis of The Life and Times of Scrooge McDuck.
• The Ultimates: Bucky mentioned one of his daughters: Sharon Carter.

Fan Works

• MonsterVerse fanfiction Abraxas:
  • Active Bone Singers were more prevalent in the time when the Titans were last active before the Mass Awakening than they are today, and various Titans have had encounters with them in different parts of the prehistoric world. Thousands of years ago, a group of shamanistic-looking Bone Singers braved Antarctica's inhospitable landscape to approach the glacier where Ghidorah was trapped in suspended animation. Godzilla thinks upon smelling Monster X and learning what they are that Vivienne Graham is a more northern breed of Bone Singer than the ones that Godzilla previously encountered. Thor had quite a close relationship with Bone Singers in his time (heavily implied to be Old Norse or a precursor to those people), recalling several songs and rituals that they performed, including a galdr that they sung over their dead to keep them from rising again.
  • The island of Yonaguni is all that geologically remains of the seafaring City of Mu which Manda's ancestor guarded, and the Yonaguni Monument is in actuality a heavily-eroded stone tomb housing the previous Manda's corpse. It's unknown how the previous Manda died or how Mu collapsed and vanished from history.
• Doctor Who fanfiction Gemini: One of Ax-Crazy Serial-Killer Killer Captain June Harper's signature trick-shots is based on a "Taska Venkman" series of spy movies.
• Neon Genesis Evangelion fanfiction Ghosts of Evangelion: Because it's a series of vignettes in anachronic order, it has tons of these. Many get resolved in later chapters. However, there's a pretty big time skip with no chapters set between 2047 and 2080. In those last chapters, characters refer to a great many events that occurred during those decades without explaining much detail. For instance, Asuka and Shinji's daughter Ryuko refers to her children and grandchildren, but we don't know how many she has, whether she's happily married, or much else about her personal life. It also seems that some characters have died in the interim since they'd be expected to be present otherwise, but the characters don't spend time discussing things they'd all know already.
• The Haunted Mansion Fan Verse The Mansionverse: No one precisely knows where the Haunted Mansion itself came from, nor what happened to The Old Gods.
• Pokémon Reset Bloodlines has these aplenty. When it grew into an Expanded Universe, many of them were explored in sidestories:
  • At the beginning, it's revealed that Professor Oak made the world a better place 40 years before Ash awakened in the Reset timeline. The details at first are mostly unknown, save for the fact that thanks to his efforts, Pokémon are for the most part less agressive and more tolerant of humans. The story also drops an early hint that he and Professor Hastings from the Ranger Nations are friends and often work together in secret, despite their nations being in a state of cold war with each other. The Oak & Hastings Gaiden reveals that they worked together using technology behind Hastings's Capture Styler to develop a machine capable of pacifying aggressive Pokémon. However, they agreed to keep the bigger specifics a secret and have Oak take full credit for it.
  • There's also the aforementioned Great Offscreen War between Trainer nations and Ranger nations. Not much has been explained beyond the following points:
    • They ended decades ago and both sides are currently in a cold war state.
    • They were horrible.
    • The Draconids of Hoenn ended up allied with the Ranger nations as a result of territorial disputes with Sootopolitans, and this causes problems in the present day for Hoenn.
    • The incident that caused it to explode was the attack of a Gyarados school and the disagreement over catching or relocating them somewhere else so they wouldn't hurt anybody.
  • Georgia goes through a mental list of gym leaders and Elite Four who had to be removed for committing crimes shortly after she was introduced. In order of increasing severity of their crimes, a Flying-type gym leader who was a Peeping Tom, a Bug-type gym leader who was a home invader and burglar, a Normal-type Elite Four who was involved in rigged matches, a Poison-type gym leader who committed sabotage, a Ghost-type gym leader who committed several murders and a Dark-type gym leader who was the leader of an Apocalypse Cult. The Ghost-type gym leader was elaborated on, and it turns out he was responsible for murdering Georgia's parents as a Serial Killer, thus providing the motivation for Georgia to become a Buster.
  • An infamous criminal known as Twenty Gyarados Bill is cited as the cause of the current limit for six active Pokémon per trainer. His story is explored in his own gaiden.
  • The Fisher Clan are stated to have the Victreebel family as their signature Pokemon, with the clan winning many battles with them in the past. The Jeanette Interlude sidestory elaborated on that and it turns out the reason Victreebel is their signature Pokemon is because the founder of the Fisher Clan was a Victreebel Bloodliner.
  • In the Big P Pokemon Race Interlude, Lara Laramie says her family has lived in harmony with wild Pokemon since her grandfather's time. The Laramie Gaiden explores how Lara's grandfather decided to establish the Pokémon reserve.
• Deconstruction Fic Challenge of the Super Friends: The End has the Legion of Doom enter another universe. Cryptic references are given constantly to this world's past and how it got to be that way, but nothing is outright stated, leaving the reader's imagination to connect the dots. The characters are just as baffled as the reader.
• With Strings Attached is loaded with these, both overt and subtle. Examples include:
  • The Idris' attic is filled with artifacts that don't quite belong there, notably a stack of books in several different languages.
  • The Deep Gap. What created it?
  • All the crumbling towns and cities of Baravada. Shag and Varx toss off a line about how the Dalns gods are somehow responsible for them, but don't elaborate.
  • The Tayhil invasion. What exactly happened during that?
  • The Wizards' University, where Grunnel once taught and where Brox is currently doing research.
• What About Witch Queen? has some, mostly used to expand the world. For example:
  • Tampere Empire is mentioned a few times as the biggest country in the region and a neighbor to both Corona and Arendelle.
  • There exists Far East. Tampere focuses on politics there and Southern Isles have ambassador there, but nothing else is ever said.
  • Southernmost Lands, an apparent stand-in for America of Era of Discoveries, with Mayincatec names and kangaroos, where everyone can allegedly start a new life.
  • Non-geographical examples include the Noodle Incident that caused Hauser to be Reassigned to Antarctica and hate Ferdinand, as well as some event in the past that caused Southern Isles to secede from Confederacy.
• The My Little Pony fic The Black Stallion doesn't explain what "nyru" are. All that's known is that they hunt ponies.
• Kreadian Funk: When first meeting Dracobot on a roof, Girlfriend takes note of the body tape near the air vents, alongside a pair of shoes with a note, questioning if a Murder-Suicide occurred on the roof. Dracobot has no clue over the implied incident, at most expressing surprise that it's all left as is. The incident in question relates to his death back when he was human, but he has since forgotten the incident and prior life upon becoming Dracobot due to his creator/mother purging that memory.
• To Serve In Hell loves doing this, as the story is told from the POV of characters either in the Everfree or in Canterlot, so whatever is going on with Equestria's geopolitical situation is rather vague;
  • The fic makes it clear that pegasi are oppressed under Nightmare Moon's regime, but also mentions pegasi enclaves as a potential place where Rainbow can send Scootaloo to safety, but doesn't elaborate.
  • Equestria is part of some kind of coalition implied to also include the Changeling Hive, which is keeping King Sombra and the Crystal Empire contained up north. Sombra is not the villain of this story, though, so the most elaboration we get on this is Kibitz being concerned that Princess Dash needs to consolidate her rule lest their allies sees her as weak and the coalition falls apart in the epilogue.
  • In a case where it's the main characters' backstory, the survivors of Ponyville spent some time surviving in the Everfree with Zecora after Nightmare Moon's return, but were eventually snuffed out, Zecora imprisoned, and most of the survivors were forced to join Nightmare Moon. Details on this time is vague, both how long it lasted and how their capture and conversion occured. The only thing that's clear is that Rainbow Dash was the first to swear fealty to Nightmare Moon.

Films — Live-Action

• The Adventures of Buckaroo Banzai Across the 8th Dimension is littered with allusions to characters we never meet and adventures we never hear anything else about, artifacts left over from the writers' original plans for a multi-media franchise, which never panned out. A lot of the ones in the film are explained in the novelization. On the other hand, the novel is written in a way to make it appear to be one episode in a much, much larger universe (that is, one is to presume that 20 or 30 other such episodes came before it), and contains a huge number of references to "previous stories" that don't actually exist.
  New Jersey: Why is there a watermelon there?
  Reno: I'll tell you later.
• In Airplane!, neither Striker nor any of his fellow crewmates will ever forget that day over Macho Grande.
• Blade Runner: "I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched C-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. ... Time to die."
• Escape from New York: The line "You flew the Gullfire over Leningrad, didn't you?" hints at Snake's past and a possible war with the Soviet Union. Also the fact that everyone thought he was dead for some reason.
• Rollie from F/X: Murder by Illusion regularly drops names of movies he'd worked on when he or Andy re-purpose equipment from those films to foil the opposition (e.g. "smoke pots from Hellraisers").
• It's implied early on in The Goonies that Mikey's gotten his friends in trouble before the film; Chunk is heard saying "I don't want to go on another one of your crazy Goonie adventures!", but no further details are provided.
• While Jupiter Ascending is actually pretty good at world-building with background references and a surprisingly interesting universe, one reference in particular feels cryptic. Caine, the part-wolf part-human super soldier, is said to have ripped the throat out of an Entitled, yet he doesn't remember the incident taking place and apparently was informed of its occurrence by his mentor, Stinger. The only indication that it actually happened is that he was court-martialed for the crime, and is no longer a skyjacker. Who the Entitled was, the reasons for it occurring, and why Caine is said to have done it in a fit of rage when we never see him acting out of rage at any point in the movie, is never expanded upon.
• MonsterVerse:
  • Based on the elaborate stone ruins dotted about in Skull Island's greenery in Kong: Skull Island, there was once a much more advanced human civilization living on the island than the current tribal people.
  • There are hints dotted throughout Godzilla: King of the Monsters that Advanced Ancient Humans cohabited the Earth with Titans in prehistoric times until a cataclysm wiped the human civilization out, and that their civilization fell because they tried to use the Titans as beasts of war and the Titans revolted.
  • In Godzilla vs. Kong, it's apparent that Godzilla and Kong's ancestors had a primeval Great Offscreen War, and Kong's ancestors originally lived in the Hollow Earth where they built a vast temple (which in the present day is abandoned, with the skeleton of a Godzilla-like Titan lying inside with an axe wedged in its bones); yet despite the movie's trailer setting up some grand revelation about how the war occurred, there's no elaboration beyond the above hints, leaving it unknown how and when the war started and ended, or also why Titanus Kong moved from the Hollow Earth to Skull Island. The novelization provides more clarification via an Iwi legend that Jia tells Andrews: it indicates that Godzilla or one of his kind fired the first shot in the war (assuming that the tale isn't biased in the favor of the Iwi's Titanus Kong deities), and Godzilla ultimately drove both the Kong species and the Iwis out of their original shared home in the Hollow Earth, forcing them to Skull Island on the surface.
• Pirates of the Caribbean:
  • Jack Sparrow makes several non sequitur references to his past exploits (e.g., "And then they made me their chief.", "Clearly you've never been to Singapore.") that enrich his character. The sequels try to tie the movies together by creating plot points out of them.
  • When we actually do get to Singapore we never find out exactly what Jack did to offend Sao Feng, so this trope appears again.
  • Also, Elizabeth's speech on Black Sam's Spit: "But you're Captain Jack Sparrow. You vanished from under the eyes of seven agents of the East India Company. You sacked Nassau port without firing a shot. Are you the pirate I've read about or not?"
  • The former again has some references in additional media, such as Pirates of the Caribbean: The Legend of Jack Sparrow we see such examples as Jack sacking Nassau port (actually by seizing control by taking advantage of an existing crisis). However, Jack is lampshaded as an Unreliable Narrator, so matters may not be as they seem.
• The Platform: Brambang and Baharat know each other from outside of The Hole. Brambang speaks as though he was Baharat's teacher at some point, but no specific details are given.
• Rio Lobo: When Hendricks is first mentioned, McNally refers to him as "Blue Tom" and mentions chasing him several times but never capturing him, although whether this is refers to Hendricks being a Civil war guerrilla or a pre-war outlaw is never mentioned.
• A mook in Ronin (1998) asks Jean Reno's former spy "Don't I recognize you?" He replies "Vienna" and shoots him. It's not relevant to the plot at all.
• Shredder Orpheus offhandedly mentions Axel's time serving in the Great Contra Wars, and that back in 1986, a nebulous year in relation to the movie's timeline, Orpheus was a member of "Latent Death Wish," a black metal band.
• Star Wars:
  • Upon its original release, A New Hope was a prime example of this, full of name-drops that have nothing to do with the plot but which combine to make the fictional world feel boundless and lived-in. References to the Imperial Senate, the Old Republic, "big Corellian ships" and the spice mines of Kessel are a few examples. Scenes that were cut in the original release, such as Han's confrontation with Jabba the Hutt, also make things like Greedo's confronting Han over something he did to wrong Jabba seem bigger. Every single throwaway line has been since filled in to ridiculous levels of detail by either the prequels or the Expanded Universe.
  • Ironically the Expanded Universe has never introduced any ship to match Han's line about the "Imperial starcruisers" that are "big Corellian ships" (he may have been referring to Corellian Corvettes. However, this seems unlikely, as they weren't predominately used by the Empire, and, while big, were nowhere near as huge as Star Destroyers and the like.)
  • More references include the Clone Wars, "that bounty hunter we ran into on Ord Mantell...," the Kessel Run, "many Bothans died...," Han and Lando's history, etc.
• Will and Ned from Unforgiven often talked about their old gang.
• The Way of the Gun makes a few references "what happened in Baltimore," some apparently shameful event in the OBGYN's past that has left him with limited opportunities.
• The term "Double D-anniversary" in What Dreams May Come. Christy and Annie are repeatedly referring to this event without giving an explanation until towards the end when we flash back to the scene where this term was coined:
  Christy: Today is kind of a D-Day. "D" for decision, I guess. About divorce.
  Annie: That'd be two D's, wouldn't it?
  Christy: I stand corrected.

Music

• The song "Red Barchetta," from the Rush album Moving Pictures, takes place in an unspecified dystopian future and relies heavily on this trope to paint an impression of the setting in the song's limited timeframe. An example:
  My uncle has a country place that no one knows about
  He says it used to be a farm before the Motor Law
  And on Sundays I elude the Eyes and hop a turbine freight
  To far outside the Wire, where my white-haired uncle waits.
  • The original short story that inspired the lyrics is a bit more descriptive of the setting, but still has examples.
• Phil Collins made up the lyrics to "In the Air Tonight" while recording, admitting that they have no specific meaning but their ominous tone was inspired by his undergoing a bitter divorce from his first wife. Attempts by people to read into the lyrics have spawned Urban Legends, including the more infamous one that suggested the song was about Collins witnessing a friend of his who drowned because somebody else refused to help, and how later Collins saw the same person at one of his concerts, directed a spotlight towards them and sang the song, driving the person to suicide.
• Talking Heads' song "Life During Wartime" is about a member of a resistance group in a war fought within the United States, presumably 20 Minutes into the Future, but doesn't give any background information. "Heard about Houston? Heard about Detroit? Heard about Pittsburgh, PA?"
• In the music video for Waterparks' We Need To Talk, the desperate girlfriend immediately checks under a bed to find a box labelled "Awsten's stuff", with various tools needed for necromancy. She uses these tools to perform a ritual, largely hinting at background for the music video's version of Awsten that doesn't (and probably shouldn't) get elaborated on.

Tabletop Games

• Magic: The Gathering uses this a lot in their Flavor Texts. Many of the early ones were given explanations later, but not all - for example, we still don't know whose uncle Uncle Istvan is supposed to be.
• Unknown Armies. Even if you manage to read through every single supplement and piece together as much as you can, there are still a lot of holes. But, since the game's major theme is a world of mystical insanity seething just below the facade of normalcy, it's generally agreed that it just wouldn't make sense if everything made sense.
• The current incarnation of the Necrons in Warhammer 40,000 was inspired largely by a throwaway line by Rick Priestley about "the quiescent perils of the C'tan" which "lay beyond the Gates of Varl". References were quietly worked into the game over the years in the form of the C'tan phase sword and phase knife, until the release of the first Necron codex where the C'tan were finally revealed as the "gods" of the Necrons, indescribably ancient and evil monsters which feed on suns.
  • There are also the two "missing" Space Marine Primarchs and their Legions. Every mention of the twenty Primarchs lists numbers II and XI as "All records deleted", and EU works have consistently refused to give any detail about who they were or what happened to them.
    • The Horus Heresy series of novels and audiobooks have touched on the subject obliquely, ranging from intimations of an accident at the gestation stage, to something so shameful and terrible that the Imperium refuses to acknowledge them, even when daemon-worshiping, civilian massacring, backstabbing psychopathic unrepentant bastards are still listed in the records (admittedly, usually with the note "Explode planet on rumour of presence", but still). The exact details have never been revealed and are unlikely to be either, this is lampshaded by characters telling each other not to even think about discussing the details.
    • The closest we get is a throw-away line saying that the Space Wolves had previously been ordered to attack a Space Marine Legion.
    • The Rainbow Warriors chapter of Space Marines remains incredibly cryptic even decades after their first appearance... Which featured one of the Sisters of Battle gunning one of their members down with no accompanying explanation. They were not mentioned again until years later when White Dwarf published a map with a "record deleted" message stamped across their honeworld.
• Now that the game numbers something like 50 books, there's very little in Rifts that was mentioned in the first book that hasn't gotten a description by now. One of the biggest examples was the Republicans, which was an off-hand mention in the first book about a technological society living in the ruins of Washington, D.C. It was the subject of several unofficial Sourcebooks (called Netbooks) until they were finally described in the Expanded Edition of the original Sourcebook. There are still a few things here and there that have gotten mentioned but still not shown. The most notorious is the permanently-open Rift in Calgary, Alberta, and the monster kingdom that's developed there, as well as others like the Blood Druids of France.
• Psionics: The Next Stage in Human Evolution: Rose Klein (AKA Mama Bear) gets one in Tomorrow's Starlight. It’s never explained what the "Albuquerque Incident” was, but it was apparently enough to get her a maximum threat rating from The Shop.

Webcomics

• Girl Genius does this a lot, helping to give the sense that it's an alternate history defined by the presence of mad scientists.
  • Among the more notable are references to what things were like before Baron Wulfenbach took over Europe, what the places ruled by less pleasant Sparks are like, and the fact that there are multiple popes.
  • Occasionally they'll also drop and/or hide names we're familiar with in places we can spot them, showing how those individuals are different in this version of history (the most prominent one is actually reasonably well known, but he's addressed by his surname where we the reader are typically familiar with his given name alone). It's Rembrandt van Rijn.
  • Sanaa's adventurous backstory is one of the few that is likely never going to be explained further.
  • A side story taking place after the main story does this. We know Agatha is settled in as the Heterodyne and Mechanicsburg is safe, but everything else is left quite vague. The Empire is referenced in a way that implies Mechanicsburg has to worry about their laws, but it's deliberately unclear who is in charge of it, what Agatha's relationship to them is, and how that relates to Mechanicsburg. The Storm King isn't even mentioned, but it could be his empire they're talking about instead of the Wulfenbach one.
• One story arc in The Inexplicable Adventures of Bob! involved a lot of clarification of throwaway details like this from earlier in the series. We've finally seen Butane the planet of dragons; we've gotten a minimally technobabblish explanation of what borfomite actually does; we've seen some court intrigue in the Nemesite Empire; Fructose Riboflavin is finally looking competent enough to explain how he got his terrifying reputation; etc.
• Dresden Codak engages in this from time to time. We never learn anything more about Reverse Moses, other than that he once parted the city to escape Aqua Pharoah.
• The Mansion of E often makes passing reference to things in distant parts of the Mansion's home country and continent.
• Several of these in The Sanity Circus, such as references to other, as-yet-unmet Scarecrows. Luther and Steven have also made reference to other Instrumen they know called March and Jupiter.
• Much of the draw of Kill Six Billion Demons is the lavish, imaginative Worldbuilding that regularly alludes to incredible events and people at work all around a main cast who rarely intersect with or expound upon them much.

Web Original

• All over the place in the Whateley Universe, because the authors have a huge bible they're working from. So there are references to superheroes and super-teams we haven't met yet, and supervillains who are 'A-level threats' according to an international scale we haven't had explained either, and also tons of references to real-world things to show how close that universe it to ours. Some of these are All There in the Manual. A B-List is world-threatening, but your average supergroup can still maybe win. Maybe. If they're lucky. An A-list, you have to call in EVERYONE. An A-list is the kinda guy you have for a Crisis Crossover.
• Also present in The Descendants, with characters mentioning minor villains they've defeated, superheroes in other cities, and seemingly pivotal moments in history that haven't even been explained in flashback. Whether or not they're just building up a Chekhov's Armoury, though, remains to be seen.
• Dr. Horrible's Sing-Along Blog makes mention to other superheroes/villains outside the main characters, such as Bait and Switch, Johnny Snow, and Hourglass, although some of them do get actual "screentime" in the supplemental comics.
• Limyaael's Fantasy Rants: Limyaael recommends that if you're going to use these for worldbuilding, use a lot of them, so the audience gets used to them as worldbuilding and doesn't expect them all to be plot points... and the ones that are plot points have the element of surprise.
• The earlier volumes of RWBY were full of references. Some of them deliberate hooks, others the result of difficulty dropping exposition about things the characters already knew. Most of the latter got filled in later on, but the series has so far kept up a supply of new hooks to replace things that are explained.
• In Dream Come True, the animals all live like normal (talking) farm animals. Yet, the horses mention the "Gypsy King" (who seems to be from another farm) and imply some sort of international society involving Gypsy Vanners. The farm animals act like they live in a kingdom, but none of this is ever clarified.

Western Animation

• Adventure Time has many references to a Great Mushroom War that happened about a millenium ago, with characters visiting old destroyed cities of our present day, old technology being littered around, and the entire planet missing a huge chunk. The actual nature of it wasn't even discussed at all until halfway through the series, but it was easily inferred to be some sort of World War III that somehow turned the world into a Fantasy Kitchen Sink somehow before any explanation began to be given.
• In one of American Dad!'s Christmas specials, taking place on the post-Rapture Earth, inhabited by demons.
  Stan: The open road is too dangerous.
  Jesus: What if we go through Sector 16?
  Stan: Sector 16? The perfect man just proposed the perfect way to die.
  Jesus: Fine! Then what about Sector 35?
  Stan: Sector 35? (scoffs) Sector 35 makes Sector 16 look like Sector 48!
• DC Animated Universe:
  • The three-part pilot episode of Justice League shows the Big Seven superheroes working together as a team for the first time. This was Green Lantern John Stewart's and Hawkgirl's first appearance in the DC Animated Universe — and the established superheroes knew exactly who they were without any introductions, having apparently heard of their off-screen exploits or worked alongside them at some not-shown point in the past.
  • Similarly, a lot of the superheroes and supervillains in Justice League just show up with their origins unexplained (and often never explained) as well; The Flash, Red Tornado, Vixen, Gypsy, Star Sapphire, Copperhead, Black Manta, and Doctor Polaris are just a few examples.
  • Another big DC Animated Universe example - The Near Apocalypse of 2009, mentioned in Batman Beyond and Justice League Unlimited's Epilogue. Nothing is known about it except it was the last battle between the first Batman and Ra's al Ghul where Talia finally betrayed him for good. No other details are known about it, and so it has become a popular subject whenever fans demand more closure to the DCAU, although Word of God says they never really planned to cover the event in any of the animated shows, and at this point it does not seem like they ever will.
• Futurama often makes fleeting references to events that happened in the thousand years between 1999 and 2999, such as Conan O'Brien losing his legs in the War of 2012, most videotapes being destroyed in 2443 during the Second Coming of Jesus, and the Sith War of 2865.
• My Little Pony: Friendship Is Magic occasionally referenced things that happened in the setting's distant past, particularly those before the advent of Celestia and Luna as princesses (and that in itself lasted for over a century before Luna's banishment 1000 years before the show begins), and then only in a roundabout way that suggests a loose series of events but no timeline.
• The Phineas and Ferb episode "My Fair Goalie" offhandedly mentions that in the 1950s in Britain, there was a highly-charged anti-palindrome atmosphere. The reasoning for this is never explained, but it forced people with palindrome names (like Professor Ross Eforp) to go into hiding, and there is apparently still prejudices today.
• One episode of Samurai Jack has the dual Villain of the Week Josephine and Ezekiel Clench frequently referring to "that boy from Kansas City" and talking as if he had put up the fight of their lives. Considering the two of them gave Jack the most trouble of any group of Bounty Hunters, this boy from Kansas City had to have been an equal to Jack or close to him. Of course, we never find out who he was or any details about him besides that he went up against the Clenches and was very difficult to take down.
• South Park will occasionally mention weird origins for their various Monster of the Week, like that the Crab People were driven underground during "the Kindling Wars," or that Mickey Mouse spends much of his time in Valhalla.
  • There's also the Coon Trilogy which gave vague origins for Kenny and Bradley, before he was born Kenny's parents where sought of members of the Cult of Cthulhu and they were somehow responsible for his Born-Again Immortality, as for Bradley he is a Human Alien living on Earth after some kind of war between two planets involving mint and berries.
  • In "A History Channel Thanksgiving" it is revealed that Plymouth Rock was the site of a wormhole (More accurate it is the site that allows a wormhole to be opened from Natalie Portman's vagina) that connects Earth to the planets Plymouth, Indi, Colthenheim, and a fourth one nobody cares about (Green Lantern Homeworld).
• Star Wars: The Clone Wars had the Death Watch start working for the Confederacy in one episode and planning to kill their leader Count Dooku during their next appearance, where they were stranded on a snow world. Why this was happening was never explained.
• Steven Universe
  • The show is always making reference to things that happened in the past that involved Gems, in particular the Great Gem War for Earth. While the cause and purpose are eventually explained as the Crystal Gems splitting off from Homeworld, many of the fine details are only vaguely alluded to, leaving thousands of years of history to explore. Additionally, many hints about the Alternate History shaped by Gems are brief images the camera's quick to pull away from. Among other things, the geography of the this Earth is completely different from our own.
  • The Galaxy Warp is said to connect Gem-controlled planets to the Homeworld via Warp. Aside from Earth, there's a mentioned fifteen additional Warps that have been severely damaged, with nary a hint as to their names and possible native species. And there's also countless newer Warp Pads that have been constructed, as Earth's Gem technology is severely out of date.
• Thunder Cats 2011 has the Cats searching for three stones of power, in addition to the Eye of Thundera. Where these come from no one knows. Also, the planet they live on is called Third Earth, and unlike in the original series, this one is heavily implied to not be our Earth, which means there must be a second earth. It's also implied that technology once existed in abundance even before Mumm-Ra's pyramid crashed there, which means it could be After the End.
• Transformers:
  • Megatron in Beast Machines has a scar over one eye which he didn't have at the end of Beast Wars. Where did it come from? We don't know.
  • Originally used, then later became a subversion during the pilot of Beast Wars. Optimus Primal references "the Great War". Since this series was originally not meant to be too closely connected to the first generation, this was more of a lore reference for long-time fans of the franchise, and this trope for everyone else. As the series went on and the creators decided to make the G1 connection more explicit, the original intent faded.
• The Venture Bros. features lots of The '70s style heroes and villains running around, we only see a handful of heroes but because of the big influence the Guild of Calamitous Intent have on the show we will constantly see cameos from lots of weird looking supervillains. How and when the Guild started is also kind of vague but it's implied that it was formed by or because of Doctor Venture's father or grandfather.
• Young Justice manages to do this in a different way: back stories and origins often go unexplained, but will still be referenced. Your average DC fan won't be phased by characters mentioning the existence of Amazons or something called "the Guardians of the Universe," but it all adds up to a rather large, unexplored world.
• The Trollz episode "Forever Amber" mentions the ancient Troll village of Angermore, who used their magic for evil but disappeared without explanation. It's hinted Simon might have something to do with it, but it's never outright confirmed.

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