->''"Arthur! Monkey out of nowhere!"''
-->-- ''WesternAnimation/TheTick''

Sometimes you have a goal in mind for your story, but you have no idea how to get there. For those times where the end justifies the means there is the ''Diabolus ex Nihilo'' or "Devil from Nothing". The Diabolus ex Nihilo is an enemy so foul, so horrible, and so evil that it needs no {{backstory}} or reasoning. It just appears from nowhere, does its job of shaking things up and antagonizing the heroes, and then promptly dies. The Diabolus ex Nihilo may get a back story in the future, but it would just be an exercise in {{retcon}}ning.

This trope can often appear in [[OriginStory origin stories]] where it's more important that the characters are introduced than that they do something sensible.

See also the GiantSpaceFleaFromNowhere, which serves roughly the same function in VideoGame gameplay -- a [[BossBattle boss]] that pops up at the end of a level for no narrative reason and with no explanation, just because there's supposed to be a boss at the end of the level or the game.

Compare the GenericDoomsdayVillain, who has no clear motive for their actions other than being "evil," even if they do in fact have backstory or context. Contrast StartOfDarkness, where the villain's backstory is explored in full detail, and OutsideContextProblem, where the mystery behind a villain's origin, [[HiddenAgendaVillain motive]], and abilities are the source of their threat. [[RuleOfThree Consider]] InvincibleVillain, where them just showing up exemplifies how bad things can get. A Diabolus ex Nihilo used by a writer to get out of a corner may be an example of ChandlersLaw.

Yes, this may also be a DiabolusExMachina if it succeeds in doing some damage. See also the AnthropicPrinciple where the appearance of an otherwise unexplained baddie forms the premise for the entire story. If they appear in the backstory, or disappear as quickly as they appeared, they may overlap with UnknownCharacter.

See also AssPull.


[[folder: Anime and Manga]]
* ''Anime/DigimonAdventure''. Apocalymon, the final villain, literally shows up out of nowhere in an outer space-like battlefield, and is fought and defeated within the course of two episodes. Apparently this was actually a case of ExecutiveMeddling, and there was supposed to be far more leadup to Apocalymon, as well as his relation to the Dark Masters.
* In ''Anime/DigimonAdventure02'', Daemon and his followers appeared randomly, had incredibly vague motivations (they want the Dark Spores... for some reason) and are defeated in a few episodes after causing some pointless mayhem. They are then quickly forgotten. The manga version is slightly better about this, in that Daemon is on Oikawa's side rather than against him.
* In ''Anime/DigimonFrontier'', after seemingly defeating [[BigBad Cherubimon]] and destroying his fortress, the heroes fight an [=IceDevimon=] who was imprisoned for terrorizing villages. The lack of hinting towards this and his relatively quick defeat suggests that his only purpose was to [[{{Filler}} fill up half an episode]].
* ''Anime/PrettyCureAllStars'' movies seem to have a tendency to use this trope gratuitously, due to lack of connection between individual ''Pretty Cure'' series. The latest of which, in [=DX3=], is the entity simply known as Black Hole. It's best described as TheHeartless of every ''Pretty Cure'' villain, ever.
* Kain, the villain of the ''Anime/TenchiMuyo'' movie "Tenchi In Love".
* ''Anime/MobileSuitGundamAGE'' gets hit with this in its final episode with Zera Gins and his Vagan Gear, though his existence was hinted at earlier in the Kio arc. He shows up at the end of the final battle, when all non-mook Vagan pilots are dead, with his only motivation and lines being "destroy the Gundams." His own side calls him a soulless warrior and their strongest pilot, and it also is mentioned he's a clone of Lord Ezelcant. Then SID shows up and merges with Vagan Gear and he goes berserk causing both sides to ally to try and stop him. Then Kio destroys his Gear SID, and that's that (though Zera himself survives). As [=AGE=] was originally conceived as a licensed game by Level-5, Zera is a very direct transplant of the GiantSpaceFleaFromNowhere.
* In ''Anime/{{Hellsing}}'': The Major has no backstory and no motivation ([[spoiler:until he meets Alucard and wants to destroy him simply for being different from him]]) other than because he simply enjoys war.
* Walpurgisnacht serves as at least a partial one in ''Anime/PuellaMagiMadokaMagica''. There's definitely some build-up to it, but it still takes a backseat to [[spoiler: the AwfulTruth behind the whole MagicalGirl system and Homura's true nature.]] In the end, its purpose in the plot is more to just show up, smash the city to pieces and [[spoiler: either kill Madoka or cause her to turn into an even more powerful witch, forcing Homura to push her own personal ResetButton and try to do the fight over again while saving her.]] Hell, if it wasn't for Homura, no one would even expect a supremely powerful witch like Walpurgisnacht to just show up and start wrecking everyone's shit.
* Grerimo from the Doma arc of ''Anime/YuGiOh''. Unlike other villains in the arc (and most in the series) he's a FlatCharacter with no backstory a all, with no explanation of why he works for Dartz. His entire purpose seems to be to introduce the viewers to Orichalcos and present it as a threat.
* ''{{Series/Pokemon}}'''s episode with the evil Togepi. It's never explained why the Togepi is evil or what its motivation was.
* ''Anime/DragonBallZ'': Despite Frieza being one of the most important villains in the franchise, he does not have much of a backstory. His race has never been identified, nor have we ever learned what planet he is from. All we really know is that his family has been running an intergalactic space pirate organization for a long time.
* In Manga/{{Naruto}}, [[spoiler: Kaguya]] shows up out of nowhere (only being mentioned about forty chapters prior to her debut as being [[spoiler:the mother of the Sage of the Six Paths]] and dead for centuries), is revealed to be responsible for ''all'' of [[SpotlightStealingSquad the Uchiha]] turning evil, and gets sealed away after a relatively short fight. Her entire purpose is essentially to take out Madara because the author accidentally made him too strong. Despite being several magnitudes stronger than him (she is the single most powerful being in the entire world) she had no true combat experience, so she was easier to defeat.
* The climax of ''Anime/YuGiOhTheDarkSideOfDimensions'' has [[spoiler:the Millennium Ring corrupting others, and bonding with Diva to create a reality-warping monster]], but how it does so [[spoiler:with Zorc and Yami Bakura gone]] is never explained.

[[folder: Comic Books]]
* ''ComicBook/{{Superman}}: The Man of Steel'' #17 introduces the most (in)famous Devil from Nothing: [[GenericDoomsdayVillain Doomsday]]. He basically emerges from the bowels of the earth, squishes a bird, and then goes on a killing spree for no good reason. He's pretty much there just to kill Superman and kick off the "Death" and "Rebirth" story arcs. Later stories revealed his origins, however.
* Darwyn Cooke's ''ComicBook/DCTheNewFrontier'' spends so much time dropping obscure DC character names that it never creates a fleshed out back story or motivation for "The Centre"--a giant living island of dinosaurs determined to cleanse the Earth and then the Solar System. Ironically, the Centre itself is from an obscure source--Dinosaur Island, a LostWorld featured in several "Weird War Tales" comics. Its existence was never previously explained, and Cooke decided to reinvent it as an alien menace.
** It seems to briefly explain its motives by possessing an {{Expy}} for Dr. Seuss, who writes it down in a story before killing himself; it reveals that it's a prehistoric entity which tired of humanity's ''noise'' and yearns to leave Earth to explore the solar system. This will require exterminating humanity for... some reason.
*** Its plan was to wipe out humanity so the Earth can heal itself from all the damages humanity has done.
* The BigBad in DC's ''ComicBook/FinalCrisis'' wasn't {{ComicBook/Darkseid}}. It was a multiversal vampire, the Dark Monitor Mandrakk. This means exactly what you think it does: he eats stories. Mind you this is explained and there is a lead up to it, but if you didn't read the ''Final Crisis: Superman Beyond'' tie-in, he seemed to come out of nowhere. Writer Creator/GrantMorrison did, however, intend for ''Superman Beyond'' to be an integral part of the story, and it is included in (most of) the trade editions of ''ComicBook/FinalCrisis''.
* A ''Franchise/{{Godzilla}}'' comic had Big G be sent back to the time of the dinosaurs, where he was attacked by a giant dragon... ''thing'' that was there for some reason; he manages to just barely beat it before being returned to the present.
* The feral vampire hag that turned Cassidy in ''ComicBook/{{Preacher}}''. She appears biting his neck, gets shot by his brother, and falls back into the bog, never to be seen again.
* The vampire that turns Lord Andrew Bennett, title character in ''ComicBook/IVampire''. He turns up while Bennett is out riding, mesmerizes him, gives a [[MotiveRant little rant]] about hating Bennett's positive outlook on life and wanting to show him the dark side and generally screw his life up, bites him, and then promptly gets staked by him. Then Andrew makes it home, filled with angst over his new condition, his wife agrees to be turned by him so that they can spend eternity together, she promptly turns evil, decides to take over the world, declares Andrew to be her enemy when he tries to talk her out of it, and flies off to begin her campaign. And there's your central plot and background set, now on with the episodic story.
* In GreenLantern: Rebirth, Hal Jordan's 90s FaceHeelTurn is explained and excused as a result of his possession by Parallax, a "Fear Entity" and literal GiantSpaceFleaFromNowhere. Parallax has since become the BigBad of a crossover event, [[RetCon one of the cornerstones]] of modern GL Continuity, and was depicted as the giant floating CGI head of Clancy Brown in TheMovie (for better or for worse). So while he is a Giant Space Flea from Nowhere, he's a beloved one.
* ComicBook/TheJoker is this; his backstory was introduced [[ComicBook/TheKillingJoke much, much later]] than the character and even in there, he outright stated that's probably false. Despite that he's still managed to rack up a body count any villain worth their salt would be jealous of, and is the person regular (and super) criminals tell stories of to scare one another.
* ComicBook/{{Severed}} has the unnamed AmbiguouslyHuman salesman who goes by the name of Mr. Fisher (along with several others, all of them false). "Fisher" is a mysterious man who eats children to consume their dreams. No reason is ever given for this. "Fisher" claims to be [[{{ReallySevenHundredYearsOld}} hundreds of years old]], and indeed, he never ages at any point in the comic. No backstory is ever given for him.

[[folder:Fan Works]]

* The ''Fanfic/PonyPOVSeries'' has the first BigBad [[spoiler:Loneliness]] who's origins have never been explained and several potential ones are offered, but nothing concrete is ever given. She just [[spoiler:shows up in Trixie's head as her EnemyWithin]]. However, this was invoked by WordOfGod, as not giving her a set origin just [[NothingIsScarier makes her that much more terrifying]] both in universe and out.
* In ''Fanfic/TheBridge'' an arc villain who shows up late into the story is a gumiho from Carrea, who's chased the kirin, Ki Seong, all the way to Equestria. There isn't any indication she's tied to the BigBad or any of Grogar's students like King Sombra or Queen Chrysalis. She's just an obscure, dangerous entity hardly anypony knows of that shows up without warning. It's later revealed that [[spoiler:her arrival was due to [[ItMakesSenseInContext an out of control army of filly Destroyahs]] accidentally destroying the ward Ki Seong kept, breaking the seal keeping the Beautiful Terror at bay.]]


[[folder:Films -- Animated]]
* The ending of the American ''WesternAnimation/AstroBoy'' movie. Just as the day is saved and everyone is celebrating, a giant sun-shaped alien with tentacles that shoots lasers out of its one giant eye attacks the town. No reason, no foreshadowing, someone just shouts "Alien!" and it's there. It's probably one last ShoutOut to the Artificial Sun from one of the earlier Astro Boy series.
* ''WesternAnimation/TheThiefAndTheCobbler:'' The Mighty One-Eye, ''and'' the entire race of [[AlwaysChaoticEvil monstrous]] [[RedRightHand One-eyed]] men he is the leader of (simply called the "One-Eyes") simply appear into the film without any kind of backstory. They want to conquer and destroy a Golden City, also without any explained motivation.
* In ''Disney/LadyAndTheTramp'' there is [[YouDirtyRat a rat.]] This rat appears just ten minutes before the end of the film, [[WouldHurtAChild tries to murder a baby,]] fights the Tramp one-on-one, wounding him and [[OhCrap posthumously has the Tramp sent to the pound, where he is certain to be put down.]] He has no lines, has no known motive and is [[ForTheEvulz utterly evil throughout.]]
* In ''WesternAnimation/TheLEGOMovie'', [[SequelHook the Duplo aliens]].
** This is true to the characters, but the audience knows that [[spoiler:they're from a previously separated Lego bin in the real world]].
* The Loc-Nar from ''WesternAnimation/HeavyMetal'' is never given a backstory, but it's the embodiment of Pure Evil that drives all the vignettes in the movie.
* In the climax of ''Disney/TheFoxAndTheHound'', when Amos Slade and Copper pursue Tod, an enormous [[BearsAreBadNews bear]] appears out of nowhere, attacking and almost killing Slade and Copper. Tod, seeing Copper in danger, returns to fight the bear and [[SaveTheVillain save his pursuers]], and the bear gets a DisneyVillainDeath. The bear was either hungry and hunting, or, more likely, defending his territory from the intruding human and dog.

[[folder:Films -- Live-Action]]
* The Whale Probe in ''Film/StarTrekIVTheVoyageHome'' is never given any backstory or origin. It's the quintessential BigDumbObject that exists to make [[TheKirk Jim Kirk's]] court martial more of a hero's welcome. (The probe was eventually given a back story in the book [[ExactlyWhatItSaysOnTheTin ''Probe'']].)
** [[JustifiedTrope Justified]] in Spock's exact line, "Only human arrogance would assume the message 'must be meant for Man'." One might imagine it was quite chatty with the cetacean life it was sent to contact.
** According to the creators, having their conversation with the whales at the end translated was considered and rejected. Given the brevity of said conversation, it didn't go well.
* ''Film/StarTrek'' (2009): Nero appears from thin air (a [[LightningCanDoAnything lightning storm]]... InSpace) and begins a genocidal rampage through the galaxy that first involves copious amounts of Klingon and Federation ships, but then involves Vulcan and Earth. He rarely speaks and his back story is explained in during a 10 second holographic powerpoint presentation. His only real purpose is to create a new timeline for the original Star Trek characters to be [[ContinuityReboot rebooted]] into. A full backstory was created in a tie-in comic, but the Powers That Be have proclaimed it not canon.
* ''Film/TheFifthElement'' introduces The Great Evil, an angry, black sphere that doesn't even have a proper name let alone a motivation. But how would Bruce Willis find a cute thousand-year-old alien girl to nail without it?
* The shark from ''Film/{{Jaws}}'' has no reason to be so big, eat people, and sink boats. But thank goodness it is and does because Roy Scheider and Richard Dreyfuss are a match made in heaven. Of course, how much motivation does a ''shark'' need? Occasionally animals realize humans are pretty easy to kill and start eating them, they tend to keep doing so until they die. It helps that for most of the movie, the townspeople [[IdiotBall make little to no effort to avoid the maneating shark they know is sticking around the beach.]] The attempt to [[RetCon give it]] a more detailed backstory and motivation in the sequels is the TropeNamer for VoodooShark.
* ''Film/{{Krull}}'': The Beast appears from outer space, invades the world and randomly crashes wedding parties all in the name of being bad. While the backstory of the Cyclops indicates that the Beast has done this sort of thing on other worlds before, there's otherwise no backstory for the Beast itself explaining where it came from and why it decided to go about invading worlds.
* In ''Film/TheDarkKnight'' ComicBook/TheJoker has no StartOfDarkness, no backstory ([[MultipleChoicePast none that you'd believe, at any rate]]). He's just ''there'' at the start of the movie to wreak havoc, havoc and more havoc, [[ForTheEvulz just 'cause]], which actually serves to make him even scarier than he might be otherwise. As Alfred puts it: "[[ForTheEvulz Some men just want to watch the world burn]]."
** The SequelHook in [[Film/BatmanBegins the previous film]] does strongly imply that he escaped from Arkham, but that only explains where he came from ''immediately'' prior to showing up.
* Many [[WerewolfWorks Werewolf Movies]], such as ''Film/AnAmericanWerewolfInLondon'', ''Film/GingerSnaps'', and ''Film/{{Wolf}}'', in which the protagonists are bitten and become werewolves, do not go into very much detail, if any at all, in explaining where the original werewolf came from--or the werewolf who made them, or who made that werewolf, and so on.
* ''Film/FrankensteinConquersTheWorld '': The "International" cut climaxes in a fight between Frankenstein's Monster (in city-stomping {{kaiju}} form) and a giant octopus who suddenly shows up out of nowhere. Not only that, but it's a famous [[MisplacedWildlife Japanese Mountain Lake Octopus]], as most of the action takes place in the "Japanese Alps." Although it was filmed at the request of the American distrubutor, he apparently felt the end result was just too silly. The scene was cut from both the Japanese and American versions, but for reasons unknown, was kept in the "International" cut (English language, but for territories outside America.)
* Monster X/Keizer Ghidorah from ''Film/GodzillaFinalWars''. He just appears out of nowhere (though it's implied he was inside the meteor "Gorath" that was heading to Earth), fights Godzilla to a draw, transforms into his more-powerful form, nearly curb-stomps Godzilla to death, and then is ultimately defeated after Godzilla gets a power boost.
* The murderous robber dressed like Santa Claus from the beginning of ''Film/SilentNightDeadlyNight''.
* The killer in ''[=HellBent=]'' is given no origin or motivation, never has his name or actual appearance revealed and isn't even mentioned in the credits. Also, making a literal example of the trope, he's dressed as the devil.
* The Leopold and Loeb-esque duo in ''Film/FunnyGames'' give various conflicting accounts of who they are and where they came from, but they're obviously all lies. They have no backstory and no reason to exist except to serve as villains for the movie you're so sadistically viewing, YouBastard.
* ''Film/LordOfIllusions'': The BigBad Nix is an EvilSorcerer with immense eldritch powers, which he states he will soon use to kill all of humanity. Where he came from or how he got his powers is never explored. When someone questions what he is, he simply replies "a man who [[AGodAmI wanted to be a god]]... then changed his mind".
* ''Film/TheHitcher'': When the police arrest [[SerialKiller John Ryder]], they can't match his finger prints to any existing criminals, nobody knows anything about him, and even his name is undoubtedly an alias (in the remake, it was stolen from one of his victims). It's as if the desert just spat out Death in human form.
* ''Film/{{Cloverfield}}'': Unlike most giant monster movies, this one doesn't bother explaining the creature's origin, since the main character's viewpoint is too low on the ground. Thus, no scenes with generals or scientists standing around providing exposition. It just shows up and rampages around New York City.

* ''Literature/TheSilmarillion'' by Creator/JRRTolkien has [[EldritchAbomination Ungoliant]]; she is said to have "descended from the Outer Darkness, maybe, that lies in Eä beyond the walls of the World." She destroys the Two Trees and almost [[DidYouJustPunchOutCthulhu eats Morgoth]]. After breeding with lesser spiders, she just... wandered off.
-->"Some have said that she ended long ago, when in her uttermost famine she devoured herself at last."
** ''Literature/TheHistoryOfMiddleEarth'' gives more details, with Ungoliant originally written as an EldritchAbomination 'personification of primeval night' before the world was made, and later this being changed to her being a Maia and former disciple of Morgoth who grew strong enough to equal him in his long years of imprisonment. Also, Ungoliant was originally planned to re-enter the story -- Eärendil slew her in one of his adventures on the way to Valinor. It's likely this would have ended up in ''Literature/TheSilmarillion'' if Tolkien had ever finished that part of the story.
* In ''Literature/TheSilverChair'' (the fourth installment published in ''Literature/TheChroniclesOfNarnia'', and the sixth in terms of InUniverse chronology), Tolkien's pal Creator/CSLewis gave us the Green Lady. We know she's a "Northern Witch" who might be somehow connected with the infamous [[Literature/TheLionTheWitchAndTheWardrobe White Witch]], but that's about it.
* With the exceptions of Blaine the Mono and Andy the Messenger Robot (Many Other Functions!), pretty much every robot in ''Franchise/TheDarkTower''. They show up, kill, maim, or psionically alter someone, then are either destroyed or returned to hibernation.
* "The One" from ''Literature/{{Animorphs}}.'' It is a literary GiantSpaceFleaFromNowhere, introduced in the very last book after the [[PuppeteerParasite Yeerks]] are defeated. There is no explanation of where it came from or what it wants, it merely becomes the remaining Yeerks' [[AGodAmI new god]], [[TheAssimilator assimilates]] Ax, shapeshifts to a bunch of random things to freak the heroes out and gets its spaceship rammed. Creator/KAApplegate's [[WordOfGod comments]] seem to indicate that she just wanted the good guys to get screwed by a new war and created a DiabolusExMachina to let them go out in a blaze of glory.
** Whatever it was that sent Jake to a BadFuture, as some kind of test, in ''The Familiar'', the definitive BizarroEpisode of the series. Some fans wanted it and the One to be the same thing, if only to make each have ''some'' overall relevance, but WordOfGod shot the idea down.
* In the ''Literature/WarriorCats'' series, the BigBad Tigerstar had nine lives at the beginning of the (then) final book, ''The Darkest Hour''. In order to avoid making him seem like a pathetic weakling, the authors had a random cat called Scourge show up, kill Tigerstar all nine times, kill ''the protagonist'', Firestar, and take over the Clans. And then Scourge died.
* Creator/SimonaAhrnstedt gives us Carl-Jan Rosenschiöld in her debut novel ''Literature/{{Overenskommelser}}''. To be fair, this novel has three villains (because one creep obviously wasn't enough), whose misogyny is disgusting even by the standards of the time in which they live (the 1880s). But the other two are at least given backstories, which can somewhat explain how they ended up being that way. But with Rosenschiöld, the guy is just there to be evil! He's a sadistic serial abuser of women, who only wishes to marry female protagonist Beatrice (who's like forty years younger than him) because he wants a virgin. We do get to see him die, but not until after he has [[spoiler: brutally raped and almost killed Beatrice on their wedding night.]] Only after his death are we given some backstory: Rosenschiöld has murdered one previous wife and driven another previous wife into suicide. But we're never told how he could become so evil.

[[folder: Live Action TV]]
* ''Series/StarTrekTheNextGeneration'''s pilot episode introduces "Q", a god like entity that begins harassing the crew seemingly for the sake of it. He simply appears on the bridge and creates unnecessary drama. While he eventually becomes a beloved character by the end of the series, he was unimportant to the plot of the pilot. WordOfGod says that the pilot was originally going to be one episode, but ExecutiveMeddling forced it to become a two part episode. So Q was made up to fill the extra hour.
* ''Series/StarTrekTheOriginalSeries'' had the Doomsday Machine from the episode of the same name, a giant weapon that flies through space eating everything it comes in contact with, up to and including entire planets. Spock believes it came from another galaxy, and Kirk theorizes it may have been built as a form of MutuallyAssuredDestruction in a war, intended as a bluff or deterrent but ultimately used, however the true origins and purpose of the machine are never revealed.
** The ExpandedUniverse novel "Vendetta" by Creator/PeterDavid reveals that it was designed to destroy the Borg.
* The enemy from the ''Series/DoctorWho'' episode [[Recap/DoctorWhoS30E10Midnight "Midnight"]] -- we never see its true form, or learn its name. It just appears out of nowhere, possesses Sky, places the Doctor and everyone with him in grave danger, [[spoiler:and is eventually defeated -- but certainly not killed -- by a random bystander, as it has incapacitated the Doctor]]. Considering how often the Doctor exhibits an encyclopedic knowledge of... everything... throughout his adventures, many count the episode as one of the eeriest in all of ''Doctor Who'', to the point of ThatOneCase.
* In ''Series/KamenRiderDecade: All Riders vs. Great Shocker'', there's King Dark, the Big Bad of ''Series/KamenRiderX'', who only rises after all the other villains are killed. It was never hinted anywhere in the movie that he would even appear at all. Since there is already a personification of the Great Leader, recurring Bigger Bad of the Showa era in [[spoiler:the eponymous Decade]], it means that there are two Great Leaders running amuck. He was probably just included to give an excuse to use the giant ''Film/KamenRiderJ'' (the movie did say ''All Riders'').
** And then [[spoiler: [[Film/KamenRiderZO Doras]] shows up in Decade's GrandFinale after dealing with both [[VillainProtagonist Tsukasa]] ''and'' [[TheRemnant Super Shocker]] almost out of nowhere.]]
* The creators of ''Series/{{Merlin 2008}}'' promised in an interview that the end of season four would end with an intriguing CliffHanger in which a previously seen "evil" character would reappear. Most fans bet their money on Mordred. However, it turned out to be something completely random. In an early season four episode Merlin discovers a dragon's egg, hatches it, and calls the baby dragon Aithusa, said to be a symbol of the forthcoming Golden Age of Camelot. The audience was given absolutely no reason to believe that Aithusa was anything but a harmless baby dragon, who is not seen or mentioned until the end of season four, where it appears in the forest to heal an injured Morgana for no apparent reason and fly off again.
* In Series/BuffyTheVampireSlayer, the First Evil is the CosmicHorror personification of evil. It wants to make people hurt and sin because, well, it's ''evil''. There's not really much else to say about it, aside from what's on the tin.
* In ''Series/BreakingBad'' the Aryan Brotherhood, though more normal than other examples, serves this purpose. They come out in the final season with not much build up, being Neo Nazis is good enough to explain why they are bad guys and are so good at what they do (mostly killing and breaking people) that they kill any other conflicts the series had that is not them.

* In Hesiod's ''Literature/{{Theogony}}''--an early TropeCodifier of Myth/GreekMythology--Typhon is one of these. He shows up out of nowhere to wreck havoc after the Olympians win their war against the Titans and Giants. Zeus defeats him and the world is finally at peace. Some later retellings either edit this bit out for being too random or write the battle as a more grandiose affair.
** Various tellings of the story change a bit of that; Typhon is described as a child of Gaia and Tartarus, set against Zeus by Gaia when she realized his rule wouldn't be much better than his father's. The battle was less a curb stomp, with Typhon having the edge early on (ripping out Zues' tendons) before being defeated by having a mountain dropped on him.

[[folder:Professional Wrestling]]
* The Wrestling/WorldWrestlingFederation has done this twice with Underfaker and Fake Kane. They showed up, confused people about their relationship to Wrestling/TheUndertaker and Wrestling/{{Kane}}, were eventually defeated by the real thing, and then vanished.
* Wrestling/{{Boogeyman}} in Ohio Valley Wrestling. However, after about three appearances, officials began to anticipate his coming and took measures to stop him, even contacted law enforcement. Nothing they did ever worked and he would quickly depart into ether almost as quickly as he arose. Oh, and he was a "[[NominalHero heroic]]" version, as the crowd [[EnsembleDarkhorse quickly took a liking to him]], to the point he was [[{{face}} cheered]] when he interrupted handicap match between the already injured [[Wrestling/MickieJames Alexis Laree]] against Wrestling/BethPhoenix and Shelly Martinez and [[RootingForTheEmpire attacked Laree]]. So Boogeyman turned to mainly beating up wrestlers the audience did not like, making him even more popular. Unlike most examples, Boogeyman did have an explained though nonsensical motivation, he wanted to be a professional wrestler. He was eventually given a {{backstory}} on WWE Smackdown too.
* Wrestling/KevinSullivan and his army [[WhenEldersAttack attacking]] Ring Warriors Grand Champion Bruce Santee. Turns out they did so exactly [[InvokedTrope because people thought they were obsolete.]][[/folder]]

[[folder: Tabletop Games]]
* ''TabletopGame/LegendOfTheFiveRings''' notorious Hidden Emperor story arc featured Goju Adorai. He appeared halfway through the arc which continued to focus on other evil characters such as the Kolat, Onnotangu, and the possessed Toturi. Adorai finally shows up during the climatic battle at Oblivion's Gate as the leader of the Lying Darkness's forces where he is defeated with virtually no information ever given about his back story or motivations.
** The [[EldritchAbomination Lying Darkness]] as a whole. The hell it come from?
* People have spent years thinking of ever-sillier ways to defeat ''TabletopGame/DungeonsAndDragons''' Tarrasque, but what the hell ''is'' it?
** Wiki/TheOtherWiki has [[http://en.wikipedia.org/wiki/Tarasque a page on the original legend]].
** [[{{TableTopGame/Spelljammer}} One source]] implied that Tarrasques (there exists more than one, once you travel between the Spheres) are docile lizard-like lithovores that react poorly to being away from their native planet.
** Pathfinder explains it as the spawn and herald of the settings main evil god.
* By definition, any RPG modeled after the CosmicHorrorStory will tend to feature these.[[/folder]]

[[folder: Theater]]
* Don John in MuchAdoAboutNothing. It would have taken Will all of 2 minutes to write one line about him being angry at Claudio for some past slight, but instead he wrote the character to be evil for evil's sake.

[[folder: Video Games]]
* Jenova in ''VideoGame/FinalFantasyVII'' appears from the sky two thousand years ago and murders most of the planet's population. After being dismembered and frozen she is revived in modern times and starts all over again. No motive or origin is ever given.
** Sephiroth hints that the cycle of parasitic destruction is Jenova's true purpose: it crashes into a planet, sucks out the Lifestream energy, and then leaves to crash into another planet. However, it's very vague at best. Sephiroth's goals may be his own, rather than an extension of Jenova's. However, in ''Advent Children'' Sephiroth ''does'' explicitly claim that he shall sail the Cosmos to find another planet to find a shining future, like his mother once did. So maybe he really ''is'' following Jenova's Goal after all. As usual of the trope, the explanation comes 10 years after the game and from a different writing team.
** In ''VideoGame/DirgeOfCerberus'', Omega Weapon's purpose is similar to Jenova's: to take the life energy of the planet and find a new planet when planet-shattering catastrophes happen.
* Necron in ''VideoGame/FinalFantasyIX''. The last boss of the game, it is basically the god of death, and where he comes from, how you get to the area he resides in, or why he wants to kill you all is not even close to explained.
* Sulphur from ''VideoGame/PhantomBrave'' is this monstrous demon thingy that wants to kill everyone. Nobody knows why, nobody asks why.
* ''VideoGame/ChronoTrigger'': Jenova's grandpappy, Lavos: it [[spoiler: [[GainaxEnding (he?)]]]] falls from the sky in the distant past, causing the equivalent of the [[PhlebotinumKilledTheDinosaurs Creataceous extinction]]. [[PlanetaryParasite Millions of years nourishing out of the planet's core later]], it (after an initial firestorm) emerges and [[TheEndOfTheWorldAsWeKnowIt proceeds to wreck the place]]. [[spoiler: And it was not the first time: he had done it before when the premier magicians in the world [[EvilIsNotAToy tried to use it for fuel.]]]]
** And then there's ''VideoGame/ChronoCross'', where the final boss [[spoiler: is yet again Lavos, who exists in a non reality unplace of infinite nothing never where the countless versions of people are erased over.]] Oh, and then he [[spoiler: decides to eat all of time because of Crono's actions in the first game.]]
* The Dark Star in ''[[VideoGame/MarioAndLuigiBowsersInsideStory Mario & Luigi: Bowser's Inside Story]]''--someone accidentally dug it up one day, realized that whatever the hell it was, it was ''bad news'', and immediately called upon the royal family to seal it away. [[BigBad Fawful]] thinks that it might be useful. [[spoiler:[[EvilIsNotAToy He is dead wrong]].]]
* The titular mothership of the ''VideoGame/{{Fallout 3}}'' add-on ''Mothership Zeta'' deserves mention. Without any previous foreshadowing, the [[PlayerCharacter Lone Wanderer]] is abducted by the aliens and must spend the next several hours (days, in game time) fighting his way through the mothership just to get home. At which point, the entire experience is never mentioned again. What exactly the aliens were ''doing'' with all the people they've been abducting over the past thousand years or so is left vague at best.
* [[spoiler:The Aurum]] in ''VideoGame/KidIcarusUprising'' are explicitly stated to "come from and return to nothing". [[spoiler:They are a strange robotic alien HiveMind that come from nowhere and become the main threat for Chapters 15-17, and force Palutena, Hades, and Viridi to form an EnemyMine.]]
* In the Legend of Skyloft told in ''VideoGame/TheLegendOfZeldaSkywardSword''[='=]s introductory sequence, it is told that one day, demons suddenly rose from the ground out of nowhere and started killing everyone, forcing the Goddess Hylia to raise a human settlement above the clouds to keep them safe. The plot during the game proper deals is caused by the remnants of the demonic forces, but the game's plot doesn't touch on where they came from.
* ''VideoGame/BatenKaitos Origins'' introduces [[HumanoidAbomination Wiseman]], who fits this trope to a T.
* Clockwerk from the ''Franchise/SlyCooper'' series. It's known that he was jealous of the Coopers for their superior thieving reputation, and that he turned himself into a robot to gain immortality so he could continue to hunt them for centuries. However, it is not known why he became a thief in the first place, nor does he have any backstory prior to becoming a thief (for example, if he had a family or a FreudianExcuse). It is also unclear how he was able to turn himself into a robot when he was born thousands of years before the concept of robotics even began, or if Clockwerk is even his real name.
** The Mask of Dark Earth from the third game also qualifies.
* In ''VideoGame/ResidentEvilNemesis'', there's well, [[AntagonistTitle Nemesis]] itself. Its specific origins have never been explained in any canon medium, which is weird because just about every other creature Umbrella has ever thrown at Jill and the other heroes has some kind of documentation or a plot point revealing what it used to be or how it was created. The closest one there is to an explanation is that it's a Tyrant imbued with an NE-T parasite developed by Umbrella's French division. Interestingly, Nemesis does get an origin story in the related film series.
* At the end of the Wasteland questline in ''VideoGame/BillyVsSnakeman'', a villain appears, explains that the odd sickness you've been suffering from is casued by his genjutsu/poisons/cloning technique (it's a different villain and trick depending on which primary bloodline you have), that he's been manipulating you from the very start, but has decided that you've outlived your usefulness. Then you beat him up and force him to join your team. At no point was there even a ''hint'' that the questline had a villain - you were just scavenging for shinies and picking up cool allies.
* Bad Girl in ''VideoGame/NoMoreHeroes'', the 2nd Ranked Assassin. Most Bosses have some background, history (some tragic, making them a little sympathetic), and/or motivation explaining why they're killers, but Bad Girl has ''nothing'' but rage, hatred, and insanity. No mention of friends or family, her past, any FreudianExcuse, no motivation for what she does other than ForTheEvulz. Travis takes note of it, and it's what disgusts him about her the most.
* ''VideoGame/TalesOfVesperia'' has [[AxCrazy Zagi]]. Zagi has no backstory, no motive, no discernible allegiances (he doesn't even show concern or loyalty to the other members of Leviathan's Claw), no specific goal beyond killing people ForTheEvulz (and [[{{Yandere}} getting off]] to fighting Yuri) and no concrete connection to any of the characters. He just turns up at random points, even when it makes no sense for him to do so, to antagonise the party. This, however, is ''[[TropesAreNotBad exactly]] what frustrates Yuri so much.
* Flowey from ''VideoGame/{{Undertale}}'' is a subversion. Every other antagonistic character in the story has their own motivations that ultimately render them sympathetic, but this guy seems to be the sole exception: he tries to kill you in the first five minutes [[ForTheEvulz purely for his own amusement]], and at the end of the Neutral route [[spoiler: he kills Asgore in cold blood, absorbs the human [=SOULs=], and transforms the world into a terrifying hell-dimension in which he intends to torture you forever]]. Without him, the plot of the Neutral route would be essentially unchanged, and he only shows up in the final moments [[spoiler: to provide you with a surrealistic FinalBoss battle]]. The Pacifist and Genocide routes, however, give him an excellent FreudianExcuse for his appalling behavior, and integrates his story seamlessly with the other monsters': [[spoiler: he's the reincarnated form of Asriel Dreemurr, trapped in his form without the ability to love. He's reset so many times that everyone's actions are fully predictable, and he's resorted to killing in an attempt to feel ''something''. Should you take the Pacifist route, he briefly regains his SOUL and displays remorse for his actions, seeking forgiveness from Frisk.]]
* On your way through the abandoned subway towards the end of ''VideoGame/BeneathASteelSky'', you come across a crevice that holds a tentacled, presumably gigantic monster that will kill you unless you take the right precautions. It has no discernable connection to [[AIIsACrapshoot the main threat in the game]], and there is no indication as to what it is or where it came from.

[[folder: Web Comics]]
* Parodied in ''Webcomic/{{Adventurers}}''--possibly even a direct parody of [[VideoGame/FinalFantasyIX Necron]]--when, after finally defeating the distinctly non-Space-Flea FinalBoss and fleeing his collapsing lair, the party is suddenly faced with [[http://www.adventurers-comic.com/d/20060103.html Necrevil]], "the embodiment of evil ''itself''!"... and they just keep running.
** [[http://www.adventurers-comic.com/d/0170.html Eternion on his first appearance]] is also an abrupt GiantSpaceFleaFromNowhere, but he becomes a recurring villain and arguably has more of an impact on the plot than the BigBad himself.
** While he's decidedly more human than most examples of this trope, [[http://www.adventurers-comic.com/d/0295.html this guy]] still qualifies by dint of location.
* Morthol Dryax in ''Webcomic/ProblemSleuth'', who [[http://www.mspaintadventures.com/?s=4&p=000916 pops up]], is soundly defeated 22 pages later, and isn't mentioned anywhere else. [[EldritchAbomination Fluthlu]] counts as one too, and [[http://www.mspaintadventures.com/?s=4&p=000950 appears shortly after beating Morthol Dryax.]] It's also never mentioned again in the series, apart from a MythologyGag or two in ''Webcomic/{{Homestuck}}''.
* ''Webcomic/{{Homestuck}}'' kind of plays with this trope. The [[AnachronicOrder nonlinear]] nature of the story means that for the reader it doesn't come out of nowhere, but from the perspective of most of the trolls [[spoiler: Bec Noir was this, suddenly appearing shortly after they defeated their FinalBoss.]]
* The [[http://bobadventures.comicgenesis.com/d/20070127.html Rogue Canadian Scientists]] in ''Webcomic/TheInexplicableAdventuresOfBob'' were introduced this way, as a joke threat from nowhere that was defeated in just a few panels. They return as a more serious threat about four years later.
* AwfulHospital: [[http://www.bogleech.com/awfulhospital/418.html The Dolphin.]] There are [[http://www.bogleech.com/awfulhospital/241.html a]] [[http://www.bogleech.com/awfulhospital/hellofremb.html few]] [[http://www.bogleech.com/awfulhospital/creepyshadow.gif references]] to it before it finally appears, but it's given no explanation whatsoever. Fans of the author's previous work and/or social media may be aware that he has expressed a strong dislike of dolphins for various reasons, but other than that, it's entirely this trope.

[[folder: Western Animation]]
* In WesternAnimation/CourageTheCowardlyDog, this trope is somewhat common, as some monsters and other threats normally appear in the farmhouse without any explict reason.
* ''WesternAnimation/TeenTitans''
** Slade's backstory and motives were never revealed, despite being the BigBad for the first two seasons, the DragonWithAnAgenda in the fourth, and a minor presence throughout the series. The heroes, especially Robin, speculate as to who he is, but nothing concrete is ever reached.
** Red X has no explanation or origin for his appearance, and no back story. He just appears out of nowhere and makes trouble for everyone. Beast Boy tries to speculate[[note]][[WesternAnimation/DCNation He thinks it's Jason Todd]][[/note]], but Raven says it could be anyone and no one else really gives it any thought.
** The [[MonsterOfTheWeek Monsters of the Week]] from the episodes "Stranded" (alien monster attacking a space station) and "Things Change" (a material-copying robot attacking the city) come out of nowhere and, though the characters wonder out loud what they are, are never given even a vague explanation.
* Dr. Claw in ''WesternAnimation/InspectorGadget'' is a faceless enemy that is constantly plotting against the titular hero. His organization seems to have no other purpose than to "Get Gadget". Claw's face was not even revealed until nearly twenty years after the show's run ended. Except on a toy.
* ''WesternAnimation/TransformersTheMovie'' features BigBad Unicron who drifts out of the vastness of space and starts eating things and making bargains with Decepticons. Though he appeared from the vacuum, he certainly didn't vanish afterward though.
** Further incarnations were slightly more careful with this. Armada hinted he was in the background for a while, Energon followed as a sequel, and ''WesternAnimation/TransformersPrime'' dropped hints about him every now and then before he appeared for real.
* ''WesternAnimation/ThunderCats'': In the series finale, after Lion-O fights an epic final battle against his ArchEnemy Mumm-Ra, the Ancient Spirits of Evil randomly throw "their champion," a giant warrior named Pyron, at Lion-O just to fill up the last couple of minutes or so of the episode.
* ''WesternAnimation/ThePowerpuffGirls'':
** Although not many of the villains have elaborate origins, the [[{{Nanomachines}} nanobots]] in "Nano of the North" seem especially inexplicable. They're a swarm of microscopic robots that come out of a cloud that forms over Townsville but nothing else surrounding it, start devouring all the carbon to make more of themselves, and demonstrate some kind of group intelligence in the way the cloud changed to focus the forces onto the Powerpuff Girls. Although they're all destroyed by the end of the episode, no clue is given as to their origin or why they were targeting Townsville specifically, and indeed no one even ''asks''.
** The evil alien force from "Forced Kin" suddenly comes from space to conquer Earth with no explanation, and turns out to be so strong he forces Mojo Jojo and the Powerpuff Girls [[EnemyMine to work together]].
* In the {{Backstory}} of Equestria as told in "Hearth's Warming Eve" in ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', the Windigos were these. They were said to be creatures that feed on ThePowerOfHate, but they came out of nowhere and had absolutely no explanation for what they planned to do with the winter they were causing, but they forced the three races of pony to band together, since they were able to create a beacon of friendship-powered fire to burn them away.
* In ''WesternAnimation/RegularShow'', Mordecai and Rigby are vying for a chair and bet on it in rock-paper-scissors. After being stuck in tie for 100 times, a monster from out of nowhere comes to eat the chair, they were able to make it go away by breaking the tie.
** This is actually the formula many of their episodes run by. The characters start off doing something fairly mundane, like going on a date or buying fast food, then all of a sudden, the fantastic [[MonsterOfTheWeek enemy of the week]] pops up to give the characters a new conflict.
* ''WesternAnimation/StevenUniverse'' starts out with its monsters as such. Each MonsterOfTheWeek has zero context with the story, unless Steven decides that [[FluffyTamer it's cool enough to keep around]] [[NiceJobBreakingItHero juuuust long enough to blow up in his face.]] However, revelations from later episodes slowly but surely subvert the trope; the Red Eye, for instance, [[spoiler: was a probe sent by [[ScaryDogmaticAliens the Gem Homeworld]]]], and the Centipeetle is one of many [[spoiler: corrupted, insane Gems left behind after the Rebellion.]]
* ''[[Recap/DuckTalesS2E2SuperDuckTales Super Duck Tales]]'' starts out with four relatively down-to-earth episodes, where we're introduced to Fenton Crackshell and find out how he became Scrooge Mc Duck's accountant and the super hero Gizmoduck. And the villains during those four episodes are the Beagles, who are just normal criminals and appear in many other episodes on the show outside this arc... But in the fifth episode, ''Money to Burn'', everything is changed when some alien robots randomly appear on the scene to steal Scrooge's money bin. Granted, the robots have a good reason from their perspective to steal money: they need the metal from the coins to make new robots. But they still come out of nowhere, just to make Scrooge, Fenton/Gizmoduck and Launchpad suddenly go on an adventure in space, almost kill the heroes to make axel grease and be destroyed by Fenton/Gizmoduck. And that is apparently all, that we have to know about them...