When the heroes of a story are told a myth, legend, or fairy tale, you can almost guarantee that the story is true (although not necessarily literally--sometimes the truth is [[LegendFadesToMyth filtered through generations of retelling]] and/or a primitive culture's viewpoint) and the heroes will have to deal with it at some point. This is used so often, in fact, that it's actually ''more'' notable when the heroes are told a story and it ''doesn't'' turn out to be some flavor of true--except for those cases where it comments thematically on the character's CharacterDevelopment.

This is largely a result of TheLawOfConservationOfDetail, which demands that taking time out from the main story to tell some other story must only be done when that side story is important to the main plot.[[note]]This applies even when such a tale actually ''isn't'' true, because then it's usually a metaphor for the heroes' current situation, or to teach them some lesson that they'll need to use later.[[/note]] The purpose in labeling something important as a myth rather than just explaining it outright is to build excitement, so that when the legend is later shown to be true, it brings a sense of wonder or discovery. It can also serve to foreshadow future events, while giving the author an excuse for giving only [[HalfTruth partial or deceptive information]].

Compare to PropheciesAreAlwaysRight, where it's a prediction that's virtually guaranteed to be right rather than a story from the past. These two tropes often live side by side, with the ancient legend packaged with an included prophecy.

Contrast ShroudedInMyth, where the heroes initially believe a legend that turns out to have been extremely exaggerated (if not outright false), and LegendFadesToMyth, where the reader is shown an inaccurate, mythical version of events they saw first-hand in a previous work, generally for humor or DramaticIrony.

Note that this trope is about the characters within a story being told a myth, which turns out to be based on actual events within the story's universe. This is not about an author using real-world myths in a story (though the myth the heroes are being told may well be borrowed from a real-world source). Also compare InfallibleBabble, the video game equivalent for rumors and legends imparted through {{NPC}}s.



[[folder:Anime & Manga]]
* ''LightNovel/SaiunkokuMonogatari'' begins with Shuurei telling her students the story of their country's founding, ending it by saying that according to legend, the eight immortal sages who helped the first emperor found Saiunkoku are still alive in secret among the people. This is absolutely true, and Shuurei goes on to become personally acquainted with several of them. A little later in the first arc, Shuurei begins to tell Ryuuki the story of the Rose Princess and how she married a mortal man. This story is not only true, it's [[spoiler:the story of her parents' marriage]].
* In ''Manga/FullmetalAlchemist'', the ancient Xingese legend of the Western Sage is [[spoiler:about Ed and Al's father]], while the Amestrian legend of the Eastern Sage is [[spoiler:about "Father," the BigBad of the series]].
* In ''Anime/DragonBallZ'', the legend of the Super Saiyan, believed to be the most powerful being in the universe comes up, originally in a passing reference in the Vegeta Saga, then suggested in the Namek Saga during the Namekian Great Elder's encounter with Krillin, then brought into the forefront when Goku arrives on Namek and easily mops the floor with the Ginyu Force. Notable in that, the BigBad Frieza knows about this legend as well, [[SuspiciouslySpecificDenial claiming not to believe in it]], yet is discovered to have [[NiceJobBreakingItHerod committed genocide against the Saiyans]] largely because of it. Ultimately, [[HoistByHisOwnPetard his own actions end up creating one]], in the form of Goku.
** If you buy the non-canon sequel to a semi-canon TV special ''[Anime/DragonBallEpisodeOfBardock'', the legend of the original Super Saiyan is ALSO true, and was caused by Goku's father and a StableTimeLoop. [[CanonDiscontinuity IF you buy it.]]
* In the Jaya and Skypeia arcs of ''Manga/OnePiece'', the Straw Hat Pirates investigate the legend of "Sky Island" and its City of Gold, which all turns out to be true, even down to most of the details.
* ''Anime/MazingerZ'' and ''Anime/GreatMazinger'': Dr. Hell joined an archaelogical expedition to the Greek island of Bardos, thinking maybe several ancient legends told that island was defended by an army of [[HumongousMecha mechanical giants]] were true. Unfortunately to everybody else, he was right. Myth/ClassicalMythology plays an increasingly important role in each retelling of the series, until the point of Greek gods start showing up and ''Anime/GreatMazinger'' BigBad is revealed being [[spoiler:Hades]] in ''Anime/ShinMazinger''.
* ''Manga/ACertainScientificRailgun'' has as a running gag the characters mentioning urban legends that all end up being true. It is frequently [[LampshadeHanging Lampshaded]] and otherwise commented upon.
* The second episode of ''LightNovel/{{Baccano}}'' gives us the UrbanLegend of the Rail Tracer: a monster that slowly snatches up and devours the passengers of the train [[SpeakOfTheDevil on which its tale is told on]]. Then a [[GambitPileup 3-way war]] breaks out over [[TrainJob train-hijacking rights]] and...''something'' decides to start picking off instigators and leaving their twisted and mutilated corpses. [[spoiler:Turns out that the Rail Tracer is the [[BadassNormal entirely human]] and [[RedHerringShirt supposedly dead]] train conductor that first told the story, and doesn't particularly like people messing up his train. Did we mention that he's also a not-entirely-sane assassin that likes a good RoaringRampageOfRevenge?]]

[[folder:Comic Books]]
* ''Toys/{{Bionicle}}'':
** In most cases, the Matoran consider most of the Turaga's stories as mere fairy tales. But most of them wind up becoming painfully true. From [[GiantEnemyCrab giant Manas]] to the hellish [[PlaceWorseThanDeath Karzahni]].
** In the backstory of the Matoran, which claimed that the Great Spirit brought the Matoran out of darkness to the island of Mata Nui. We later find out that it was actually the Turaga who rescued them (as Toa Metru) from their ruined city; they just credited the Spirit with giving them the strength and abilities to do so.

[[folder:Films -- Animation]]
* In ''Anime/CastleInTheSky'', Pazu believes the city of Laputa exists from the start when other say it's just a myth. He's not wrong, otherwise the movie would be a lot less interesting.
* In ''Disney/TreasurePlanet'', Jim's mother assures him in the opening scene that the planet's just a legend.
* In ''[[Franchise/DisneyFairies Tinker Bell and the Lost Treasure]]'', the song "Fairy Tale Theater" just happens to be a prophecy of her journey later in the movie that was being performed the one night that she went to the theater.
* ''WesternAnimation/MyLittlePonyEquestriaGirlsLegendOfEverfree'': The eponymous legend of Gaea Everfree starts out as a campfire tale by Timber Spruce. Not surprisingly, it is bound to become important later, although it's a subversion: the legend doesn't happen so much to be true than to be a cover story for the supernatural shenanigans already happening, [[spoiler:as a result of Gloriosa Daisy meddling with a magic she doesn't understand]].

[[folder:Films -- Live-Action]]
* In ''Film/TheSecretOfRoanInish'' the grandfather tells the legend of the selkie, which is important to the climax of the film.
* ''Franchise/IndianaJones'': The Jewish story of the TheArkOfTheCovenant and the medieval Christian tale HolyGrail are both proven to be unambiguously true. But so are some elements of Hinduism and the legend of the {{Crystal Skull}}s. Not to mention (much as some people would like to pretend it didn't happen) stories of extraterrestrial visitation, and theories about AncientAstronauts.
* A variation shows up in ''Film/UndercoverBrother'', when Eddie Griffin learns from "The Brotherhood" that all the supposed conspiracy theories about black people are true:
-->'''Conspiracy Brother:''' What do you think? Things don't just happen by accident! Sometimes people -- mostly ''white'' people -- make things happen!\\
'''Undercover Brother:''' So the conspiracies we've believed for all these years are true? The NBA really did institute the three point shot to give white boys a chance?\\
'''Conspiracy Brother:''' Of course!\\
'''Undercover Brother:''' Then the entertainment industry really ''is'' out to get Spike Lee?\\
'''Conspiracy Brother:''' Come on man! Even Cher's won an Oscar! Cher!\\
'''Undercover Brother:''' Then O.J. really didn't do it?\\
''[everyone looks away and mumbles]''
* ''Film/{{The Mummy|1999}}'':
** "Hamunaptra's a myth." ...No it isn't. And no, the cursed mummy isn't a myth either. Although the curator who says that knows very well that Hamunaptra isn't a myth. He is a [[AncientTradition Medjai]] who is ''trying'' to discourage Evy and Jonathan from looking for Hamunaptra.
** The sequels add the [[Wrestling/DwayneJohnson Scorpion King]] and the [[Creator/JetLi Dragon Emperor]].
* ''Film/{{Hook}}'' is based on this as well. That's far less "all myths are true" as it is "those books that were written are true; I know because I'm the one that experienced it, and [[LiteraryAgentHypothesis told the stories to the writer]]."
-->'''Wendy:''' The stories are true! I swear to you! I swear on everything I adore. And now he's come back to seek his revenge. The fight isn't over for Captain James Hook. He wants you back. He knows that you'll follow Jack and Maggie to the ends of the earth and beyond. And by heaven, you must find a way. Only you can save your children. Somehow, you must go back. You must make yourself remember.

* The Creator/StephenKing novel ''Literature/{{Desperation}}'' tells the legend of why an old mine was abandoned (a trapped ChineseLaborer summoned a bad spirit). There really ''is'' a monster, though actually they just DugTooDeep and set loose an EldritchAbomination.
* In ''Literature/GuardiansOfGaHoole'', The Band set out to find the [[TitleDrop Guardians of Ga'Hoole]], which are a legendary group of owls. [[spoiler:They are real and eventually The Band join them.]]
* ''Literature/HarryPotter''
** In ''Literature/HarryPotterAndTheChamberOfSecrets'', the legend of the eponymous Chamber, which Professor Binns tells to his History of Magic class and dismisses as a preposterous myth, turns out to be absolutely true, including the deadly guardian.
** In ''Literature/HarryPotterAndTheDeathlyHallows'', the 'Tale of the Three Brothers' is an exaggerated and mythified version of the truth. Justified since they're exposed to the story by someone who already knew it was true.
* In ''Literature/{{Earthsea}}'' the myth of human-dragon hybrids trapped in human form, mentioned at the beginning of ''Literature/{{Tehanu}}'', is proven true at the book's end and forms the basis for the plot of the next novel, ''Literature/TheOtherWind''.
* In ''Literature/TheEyesOfKidMidas'', the teacher explains that the mountain they're camped out underneath is called the Eye of God, and some ways away down in the valley there's a tall, thin spire that's known as the Devil's Chair. According to legend, the peak of the Eye of God was the place where the world was created, and once a year, the very tip of the mountain's shadow falls exactly at the peak of the Devil's Chair. Though the teacher admits it's merely a legend (and the mountain's shadow actually never goes near Devil's Chair), Kevin climbs the mountain, and at the top he discovers a pair of sunglasses that allow him to [[RealityWarper harness the forces of creation]]. And lo and behold, when he puts them on, he sees the shadow move fall exactly where his teacher said it would.
* In Erika Griffin's novel, ''[[http://www.amazon.com/One-Who-Waited-Erika-Griffin/dp/1411627164 The One Who Waited]]'', Alice ponders this during the course of the story, as she comes to realize that there are such things as Boogeymen and wonders if other monsters might exist as well.
* In Anthony C. Gilbert's ''[[http://www.lulu.com/content/553426 Farther Up and Farther In]]'' AllMythsAreTrue about life after death. Except, apparently, the belief that there isn't any, because the narrator is an atheist but gets sent to Hell, the Christian afterlife being the default for Westerners without other positive beliefs. Escaping from Hell (!) leads to a CrossoverCosmology where he meets Freja, Pan, Monkey and others: the final message (logically, given the opening premise) is that [[spoiler: All Gods Are One and we are One with them.]]
* In the ''Literature/TalesOfTheFiveHundredKingdoms'' by Creator/MercedesLackey, all fairy tales, from Russian to Middle Eastern to the Brothers Grimm and anything else, are true. In fact, a magical force known as the Tradition actively works to try and make them come true. Those that are GenreSavvy will use the Tradition to their advantage.
* The Bifrost Guardians by Mickey Zucker Reichert is another all myths are true, with the melding of technology to Norse myths to Christianity.
* In ''Literature/PrinceCaspian'' from ''Literature/TheChroniclesOfNarnia'': Caspian was always taught that the "old Narnians" were myths and fairy tales, then he learns that they are in fact real. The appearance of the Pevensies and Aslan also turns out to be this for many old Narnians.
* In Creator/OrsonScottCard's ''Literature/TheLostGate'' the Westillian Families are the basis of all Indo-European pantheons. It is inferred that other cultures deities, including the Abrahamic one have similar origins.
* In ''Literature/TheKingkillerChronicle'', every single story told in Kvothe's narration turns out to be relevant and mostly true sooner or later; for example, Hespe's story about the boy who loved the moon [[spoiler: is a more or less accurate representation of how the mortal world and the fae world ended up going to war.]]
* The myths and stories of TheCosmere usually correspond to some facet of the magical or historical landscape, so to speak. The local [[PhysicalGod Shards]], for instance, are usually major players in the local mythology, and their stated aims and behavior are recognizably in-character. This is clearest when comparing the religious doctrine on Nalthis (of both major factions, no less, as disparate as they are in almost every other respect) to a character's memories of being returned from the dead, but the examples are too numerous to list here.

[[folder:Live-Action TV]]
* Averted in ''Series/BabylonFive'''s episode "A Late Delivery From Avalon"--an arrival on the Babylon 5 station claims to be King Arthur, brought back among humanity after a long hiatus (when he was "taken to Avalon" on a mysterious "ship"). There is actual discussion among the main characters as to whether this could be true, since there was already a known case where the Vorlons did abduct a historical figure and used him to do their bidding in other times ([[spoiler: "Comes the [[UsefulNotes/JackTheRipper Inquisitor]]"]]). But it turns out [[spoiler: he was from the present time, suffering trauma-induced delusion from being the officer who fired the first shot that started the Earth-Minbari War years ago]].
* ''Series/GameOfThrones'': It becomes pretty obvious what Bran's dreams really are when Maester Luwin tells Bran that sure, there are ''stories'' about people who can form a spiritual link with animals, but they aren't true and would be long gone even if they were.
* ''Series/MythQuest'': Minokichi's mentor tells him the campfire story of Yuki-Onna, an ice demon. Guess who shows up later?
* Seeing as how it's a show with time travel and aliens, this trope is practically a requirement in ''Series/DoctorWho'': every time the Doctor visits a place-- real or fictional-- with a famed historical/mythological legend surrounding it, you can guarantee that it heavily involves both the Doctor and whatever monster he has to fight this time. Hell, this extends to the point where ''[[Recap/DoctorWhoS19E6Earthshock the extinction of the greater dinosaurs]]'' was the doing of one of the Doctor's enemies.

[[folder:Video Games]]
* The GameBoy game ''Final Fantasy Legend II'' (''VideoGame/SaGa2'' in Japan) avoids this. One world your characters explore has a myth that turns out to be true and another myth that turns out to be false. [[spoiler:Also, there are actually 78 "MAGI", not just 77 as mentioned at the beginning of the game.]]
* In ''VideoGame/PaperMarioTheThousandYearDoor'', Professor Frankly encounters conflicting theories on the nature of the treasure he's looking for.
** Eventually one of the theories turns out to be true: the treasure is an [[spoiler: ancient demon. But later it is revealed that the 'real' treasure was a Dried Shroom, the weakest healing item in the game.]]
** Which really isn't very surprising when you consider it was rotting for the past thousand years.
** In the same district of Rogueport that Frankly's house is located in, you can find a quirky storyteller who is glad to spin all sorts of old stories. But that tale about the horrible evil monster and the four heroes who fought it before being themselves sealed away couldn't be true, right? [[spoiler:Of course it is. The monster is a demon sleeping underneath Rogueport ''right now'' and Mario actually encounters each of the heroes in the form of talking cursed treasure chests. They're pretty nice.]]
* In the ''VideoGame/ShadowHearts'' series all myths are true, though very often in ridiculous, bizarre and over the top ways.
* In pretty much all the ''Franchise/FinalFantasy'' games, if you talk to any random NPC who tells you about some legend, the legend is bound to be true. Hidden magical weapons? Yup. Super-powered monsters? Yup. Maze-like hidden cities? Yup.
* In ''VideoGame/KingdomHeartsII'', there are TheSevenMysteries of Twilight Town, urban legends which invariably turn out to be for real when Roxas investigates (and serve as clues to the nature of the world he's been living in). But when Roxas's friends come along to do the write-up, they assume each was just a misunderstanding of something mundane.
* Bungie's ''VideoGame/{{Marathon}}'' series contains an interesting example. The second game has a ''single terminal'' midway through the game that references a S'pht creation myth where the god Yrro flung a chaotic being into the star that Lh'owon orbits. This terminal is never mentioned by any character for the remainder of the game. The myth then forms the ''entire plot'' of the third game, ''Marathon Infinity'' -- sure enough, the [[SufficientlyAdvancedAlien Jjaro (or Yrro)]] trapped an EldritchAbomination [[SealedEvilInACan inside the system's star]]. Which the Pfhor destroyed in the finale of the second game.
* In ''Franchise/{{Pokemon}}'', any myth or legend you hear about from an NPC is almost guaranteed to be a hint as to where to find a particular Legendary pokemon.
* A set of daily quests in ''VideoGame/WorldOfWarcraft'' has you investigate myths about three maidens who will grant powerful swords if you do each a favor. Naturally, all three of them turn out to be true.
* In ''VideoGame/{{Borderlands}}'', the person who sends you to kill Crawmerax the Invincible says that most people think he is a myth and doesn't really exist. Naturally, when you get to the designated spot, he shows up. Subverted in that the quest-giver is quite surprised that you actually managed to find and kill Crawmerax since [[spoiler:he made the whole thing up off the top of his head [[{{Troll}} just to mess with people]].]]
* Funny subversion in ''Videogame/LufiaCurseOfTheSinistrals'' remake. At one point you're sent to find the legendary sword, which the legends claim to have been forged by the gods and able to cut mountains in half. Just one line after that you're informed that all of that is just legend, and the sword itself is probably not even magical, but that you should get it just to boost the morale of the people. It turns our that the myth ''really wasn't'' true... but the sword is still good enough to be useful by the time you get to it.
* In ''Star Wars: VideoGame/KnightsOfTheOldRepublic'', you can learn about the creations myths of the Selkath and the Tusken Raiders. It turns out that both are true and are references to the Rakata, the creators of the Star Maps.
* In the Human Noble Origin of ''[[VideoGame/DragonAgeOrigins Dragon Age: Origins]]'', your old nanny, if prompted, will tell you the bedtime story of Hohaku, the Dog That Bit--a famous warhound that grows up arrogant and prideful, treating others like dirt and stealing their food, while striving to be chosen by its owner's son. When the owner's son chooses another hound instead, a furious Hohaku lunges for an attack and gets killed for his trouble. The correct moral Nan wants you to take away from the story is "Respect all equally". [[spoiler: Three guesses as to what [[Main/FalseFriend Arl Howe]] [[Main/DoomedHometown does to Bryce Cousland and his castle of Highever that evening]].]]
* In ''VideoGame/DwarfFortress'' Adventurer Mode, if someone talks to you about [[OurDragonsAreDifferent some dragon who razed his hometown long time ago]] or a forest where [[OurZombiesAreDifferent the dead are said to rise and stalk the living]], you can be absolutely sure he's telling the unvarnished truth. The only exception to this trope are centaurs, chimeras, and griffons, who sometimes appear on engravings but don't exist in the game world... yet. What's more, the stories will be told with impeccable detail. A thousand years on, everybody in the world still remembers which particular tooth was knocked out of the mouth of a random peasant by a marauding Bronze Colossus.
* In ''VideoGame/TheLegendOfZeldaTheWindWaker'', the intro cut scene with the story of the hero of legend and the kingdom of Hyrule turns out to be entirely relevant to the storyline, and last part of the game mainly takes place in the now flooded kingdom. Similarly, all those rumours about the 'triumph forks' turn out to be about the Triforce of Courage that Link finds in the endgame.
* ''VideoGame/TheElderScrollsIIIMorrowind'' plays with this trope, in that the particulars of a certain historical event relevant to the main plot of the game are [[TheRashomon recounted differently by different parties]].
** Played with humorously in ''VideoGame/TheElderScrollsIVOblivion'' where Sheogorath asks you (or you ask yourself if you've become Sheogorath) to fulfil a prophecy a small village has about the end of the world that includes attacks by rats and ''FLAMING DOGS DROPPING FROM THE SKY''. The prophecy is used as little more than a prank.
* Some of the local legends recounted to the protagonists of ''VideoGame/ChronoCross'' are correct but... slightly skewed.
* The entire story/legend of the Zeekeeper in VideoGame/MarioAndLuigiDreamTeam. You see a ton of exhibits and signs talking about an ancient guardian of the kingdom that saved it from harm, and well, you should probably have figured out pretty quickly that said figure turns out to be a very important character in the storyline and that he helps you take down the BigBad.
* In ''[[VideoGame/FireEmblemTellius Fire Emblem: Path of Radiance]]'', the heroes learn that a medallion holds a [[SealedEvilInACan dark god]] who will bring TheEndOfTheWorldAsWeKnowIt if freed, and it can be freed by MagicMusic or a huge war. The fact that certain people can become mindless berserkers by wielding the relic reinforces this belief. But in the sequel, ''Radiant Dawn'' it turns out to be a lie spread by the Dragon Laguz king in vain hopes that it'll prevent war between everyone in Tellius. In truth, endless war will actually awaken the goddess Ashera, who will see the wars as a sign that those living in Tellius are failures, and must be purged away to allow for a perfect world.
* In ''VideoGame/JaysJourney'', there's a subversion and a straight example. The opening crawl tells a story from the past that [[BaitAndSwitchCredits has nothing to do with the rest of the game]]. However, later in the game, Pixie tells the heroes about how the apparent BigBad, Antignarot, inadvertently got his powers from a demon named Xanabas. Xanabas later becomes a major villain and the FinalBoss.
* In ''VideoGame/KingdomOfParadise'', there is "The Forbidden Poem", which got its name because people feared that learning or reciting the poem would bring disaster. It is a beautiful poem. But the poem is about the existence of the Celestial Twins[[spoiler: and their role in opening the Toshintetsu and the gate to Seima.]]

[[folder:Visual Novels]]
* ''VisualNovel/NineHoursNinePersonsNineDoors'' spends a lot of time having characters tell you about Allice, an Egyptian mummy that was being transported in the Titanic. June believes that the ship sank because of Allice's curse, and Seven and Ace add to the legend with their own bits of info. Near the end of the game, you find the coffin where Allice was being carried, you open it... [[spoiler:and you find nothing but a key and an emblem, both used to solve a puzzle. Allice is just a way to talk about ICE-9, which is tied to the morphogenetic field, which is a powerful theme in the game]].

[[folder:Web Comics]]
* ''Webcomic/{{Digger}}'' spends more than a few strips explaining the hyena mythology surrounding their progenitor-gods "He-Is" and "She-Is", and the "badness" that came from their [[DealWithTheDevil interactions]] with the demonic [[TheCorrupter Sweetgrass Voice]]. Naturally, it's eventually up to Digger to SetRightWhatOnceWentWrong.
* In ''WebComic/TheAdventuresOfDrMcNinja'', if ''anyone'' mentions ''anything'' unusual or absurd-sounding -- like giant lumberjacks, dinosaur-riding bandito paleontologists, zombie ninjas, or the ghosts of dead NASA astronauts -- you can bet it'll not only exist but have a direct impact on the plot of the current arc.
* Myths and superstitions in ''Webcomic/TalesOfTheQuestor'' tend to be problematic after a few too many generations. Some of them end up being accurate, but for each one that actually is, you've got a few dozen that are corrupted from translation issues or pure age, and hundreds that are plain false or started up from illogical premises. It's also a rule for the setting that no one can see the future, so prophecy tends to ''always'' be wrong.
* [[http://www.skindeepcomic.com/archive/ridiculous-creatures-1/ This]] short story from ''WebComic/SkinDeep''. "How am I supposed to know what is actually fiction around here anymore?"
* In ''Webcomic/EightBitTheater'', [[PowerCopying Blue Magic]] is considered to be the "holy grail of wizardry", and the seven documented attempts at it ended in explosive failure. Then Black Mage gets the power of Blue Magic thanks to a GodOfEvil... and it turns out to be a ''[[PowerupLetdown massive disappointment]]''.

[[folder:Web Original]]
* In ''Phaeton'' if a myth isn't true already then it can become true through the power of the Enigma. Sometimes mythical versions of creatures who already exist become true, that's when things get complicated.

[[folder:Western Animation]]
* ''WesternAnimation/ScoobyDoo'' [[PlayedForLaughs plays this trope for laughs]]. Typically, something spooky is going on, but is [[DoingInTheWizard actually engineered]] by someone wanting to scare people away. Half the time, it's an InvokedTrope, as the fake monster is based on an old local legend (or, occasionally, the villain makes up a story and ''claims'' it's an old legend). Once in a while, there's [[RealAfterAll some evidence]] of ''actual'' spookiness, which the heroes may or [[GaveUpTooSoon may not]] see.
* ''WesternAnimation/JackieChanAdventures'' [[PlayedForLaughs plays this for laughs]] in an episode about Stonehenge. Apparently, it has some sort of great magical powers, but nobody really knows what it ''does''. Jackie Chan, upon being told this, sarcastically remarks "Yeah, and some people think it's used to contact aliens." The bad guys figure it must be some kind of weapon, and Jackie Chan goes into action to stop them from activating it. Amazingly, the bad guys actually succeed at pulling off their EvilPlan to activate Stonehenge, revealing to everyone present that Stonehenge does... ''absolutely nothing''. Everyone goes home, and then, in the last scene of the episode, a [=UFO=] lands at the now-deserted Stonehenge.
* ''WesternAnimation/KimPossible''. [[EverythingsBetterWithMonkeys Mystical Monkey Power]] is all about this trope.
* ''WesternAnimation/HeManAndTheMastersOfTheUniverse1983'' does this constantly. Anything that's supposedly just a myth, turns out to be real. EVERY. SINGLE. TIME.
* ''WesternAnimation/TheRealGhostbusters'' and its SequelSeries ''WesternAnimation/ExtremeGhostbusters'' follow this trope pretty faithfully:
** It's subverted in one episode of ''WesternAnimation/TheRealGhostbusters'', where the Ghostbusters must deal with a creature from Irish folklore. According to legend, the creature can only be stopped by a FourLeafClover. All the characters go out searching for one, except Egon, who, playing the role of AgentScully, insists that the creature can be captured using the same "scientific" methods they always use. In the end, the four-leaf clover fails (it was a fake taken from a parade float), and Egon saves the day by capturing the creature "scientifically", exactly as he said he would.
* ''WesternAnimation/Ben10'' devoted an episode to the Navajo legend of [[OurWerewolvesAreDifferent the Yenaldooshi]], as told by one of Max's former teammates. The monster in question is indeed real, although it turns out the legend got a lot of things wrong and it was actually an alien.
* ''WesternAnimation/{{Futurama}}'': the in-universe legends of mutants living under the city and El Chupinebra turn out to be completely true -- as does the more common myth of crocodiles in the sewers.
* In ''WesternAnimation/ThunderCats2011'', the {{Catfolk}}-populated magical kingdom of Thundera, stuck in MedievalStasis, considers [[LostTechnology technology]] to be mythical. Stories of "ships that could fly" are [[OutgrownSuchSillySuperstitions fairy tales told to cubs]]. The populace has become similarly skeptical of the existence of the Book of Omens and Mumm-Ra. In the space of one night, protagonist Lion-O and the Thunderians see their kingdom ruined when old enemies the [[LizardFolk Lizards]] invade, bringing with them ''futuristic'' technological [[SuperweaponSurprise superweapons]], given them by SorcerousOverlord Mumm-Ra. Lion-O and his Thundercats are then sent on a race to find the very real Book of Omens before Mumm-Ra can get his hands on it.
* The first episode of ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' has a StorybookOpening of the tale of "The Mare in the Moon". Despite being referred to as an "old ponytale" by others, Twilight Sparkle believes the legend has a basis in reality and is concerned by prediction of [[BigBad Nightmare Moon's]] escape from her [[SealedEvilInACan imprisonment on the moon]], which is scheduled to happen within days. Of course it's all absolutely, literally true, and [[PropheciesAreAlwaysRight the return happens exactly as predicted]].