Not every hero has an ArchEnemy... initially. Sometimes, though, a villain will be introduced who ends up being a BreakoutCharacter in his/her own right, and thus a [[MonsterOfTheWeek Villain of the Week]] becomes the villain of the series.

This can be caused by many things, from WriterRevolt, to unbridled fan response to the character, to the writers being blown away by the performance of the actor who shows up to play the role.

Note that this is the ''accidental'' creation of an archenemy, not ExecutiveMeddling of "let's make an archenemy for X-character": a Breakout Villain is one who was meant to be a one-shot throw-away that, through fan/author/executive/all-of-the-above response became not only a staple villain, but ''the'' villain of the series.

In some cases, the character may never again appear in the original authors' stories, but because of the popularity of the character, subsequent authors or even [[{{Fanon}} the fans in general]] may make their parts bigger and more integral to the mythos in question, via subsequent stories, adaptations, or simply fanon.

Sometimes, these characters become [[AntiHero antiheroes]] in their own right, [[BadassDecay with all the attendant risks.]] Most often, though, they retain their wonderful BigBad status. Can cross over with HijackedByGanon if they are turned into a BiggerBad overseeing a lot of plots seemingly masterminded by different villains.

Compare EnsembleDarkHorse, SpotlightStealingSquad. Contrast with TokenMotivationalNemesis, a major nemesis who is killed off as soon as the first story arc ends.



[[folder:Anime and Manga]]
* ''Anime/YuGiOh'': Both Seto Kaiba and the card game, Duel Monsters (Magic and Wizards back then) were originally [[MonsterOfTheWeek going to appear only once.]] Fans got interested, and sent a cavalcade of mail. Kaiba appeared again as the villain of an arc, and played a card game at the end. Fans went crazy. Then the Yu-Gi-Oh Duelist Kingdom StoryArc came out, one thing led to another, and before long, Kaiba was arguably the number-three character after Yugi and Jounouchi, and Duel Monsters was the focus of the series. If you tell someone who hasn't read the manga that Kaiba and Duel Monsters were originally one-offs, you may make [[YourHeadAsplode their brain spontaneously combust.]]
* ''Anime/NeonGenesisEvangelion'': Kaworu Nagisa: Few villainous characters have appeared for so short an amount of time (approx. 12 minutes on-screen of the 24-minute episode), yet left such an impression on any one series. Since Kaworu's appearance, and death, in episode 24 of ''Evangelion'', the fan response to his character has been so abnormally outstanding that Kaworu has appeared as a main character in nearly every subsequent incarnation/retelling/sidestory/etc. of the series, including the ''Evangelion'' manga series, ''AngelicDays'' manga, games, and the ''Anime/RebuildOfEvangelion'' series.
* ''LightNovel/ACertainMagicalIndex'' had Accelerator, who with his sheer creepiness, snark, creative use of the power to control vectors touching him and an [[EvilLaugh insane cackle]][[note]]he had several[[/note]] was so popular among the fans that Creator/KazumaKamachi brought him back, [[spoiler: albeit as a self-loathing, brought down to normal crippled Anti-Hero (Grade 4-5). He still is the most amazing character of the whole set.]]
* ''Manga/MedakaBox'': Similar to Accelerator, Kumagawa Misogi was originally just a TokenMotivationalNemesis, meant merely as a cautionary tale about Medaka's past. Before his actual debut, the only Arc Villains included a megalomaniac abnormal, and a ten-year old obsessed with justice. Once he debuted, he secured his position as the heroine's ArchEnemy and eventually [[spoiler: made a HeelFaceTurn]].
* ''Anime/GreatMazinger'' has Ankoku Daishogun, TheDragon of the story, TheRival, and a WorthyOpponent to Tetsuya Tsurugi, who in the original series, only lasted roughly 3/4 through the whole show. However, he is popular enough that he got two movie adaptation that stars him as the main villain. There is a good chance that someone who never watched the original series did not know that he is actually not the BigBad.
* ''Manga/DragonBall'' has Freeza, despite being one of many [[BigBad Big Bads]], in the series, Freeza has practically become synonymous with the franchise. He has been featured the most as the main villain of the video games, despite being the villain for half way though the series and being ''much'' weaker than Cell or Buu. Freeza's brother Cooler and the [=LSSJ=] Broly are Breakout ''Movie'' Villains who appear more than once in the ''DBZ'' movies and they are the first movie villains who appear in a ''[=DBZ=]'' video game. Especially Broly, who appears more often in video games than any other movie villain.
* ''Manga/ThePrinceOfTennis'': Hyotei was originally one of the Seigaku's arrogant rivals. However, their popularity and subsequent development allowed them to be faced a second time in the Nationals. The same treatment happened with Rikkaidai; their popularity meant that they would face Seigaku [[spoiler: in the finals.]]

[[folder:Comic Books]]
* Comicbook/BlackAdam: [[Comicbook/{{Shazam}} Captain Marvel]] was such a [[FunPersonified happy, fun, feel-good-superhero series]] at first...then Black Adam came along. Originally intended as a one-shot baddy back in the 40's, Black Adam has [[TheBusCameBack come back in force]] several years before the ''Comicbook/CrisisOnInfiniteEarths'', to become the most powerful villain/antihero of not only Captain Marvel mythos, but also one of the most powerful villains in Franchise/TheDCU. In recent years, he's proven to be more popular than the hero he was created to oppose. It is all the more interesting in that Captain Marvel already ''had'' a designated "primary villain" in the form of Dr. Sivana, who debuted alongside him in ''Whiz Comics'' #2, bedeviling the Big Red Cheese with [[CardCarryingVillain a whole deck of Villain cards]] throughout TheGoldenAgeOfComicBooks.
* Most successful ''Franchise/{{Batman}}'' villains are Breakout Villains.
** SelfDemonstrating/TheJoker: Believe it or not, the villain of villains, the Clown Prince of Crime, the one crazy bad guy who can make Satan pee in his pants just by laughing, was not originally intended to be ''the'' Franchise/{{Batman}} villain, let alone the most well-known villain in comic history. According to the other wiki: "He was slated to be killed in his second appearance, but editor Whitney Ellsworth suggested that the character be spared. A hastily drawn panel, demonstrating that the Joker was still alive, was subsequently added to the comic."
** Harley Quinn's initial role was to do little more than help smooth out a punchline with a Joker character coming out of a cake, but eventually went on to be a comparable villain in much of the ''Franchise/{{DCAU}}'' (and the comics) to even the Joker.
** ComicBook/TheRiddler was featured in a whopping ''two'' stories in his debut year (1948) before being promptly forgotten for nearly twenty years. After being brought back into the comics (just in time for the [[Series/{{Batman}} 60s show]]), he climbed his way up to the highest tier of the Bat-Rogues almost overnight.
** Scarecrow was featured in only two stories as well, neither of them memorable in the least. Then came a certain issue of ''ComicBook/TheBraveAndTheBold'' comic book that gave him his fear gas... and the rest is history.
** For decades, Mr. Freeze was a joke villain from the 60s in the same league as Calendar Man and Killer Moth. Then the ''WesternAnimation/BatmanTheAnimatedSeries'' episode "[[Recap/BatmanTheAnimatedSeriesE14HeartOfIce Heart of Ice]]" aired, and he instantly became an A-list villain and one of the most haunting and tragic characters in Batman's rogue gallery.
** In the third ComicBook/TwoFace story, Batman persuaded him to turn himself in and submit to any needed psychotherapy and surgery by loading a coin to land on its edge, and he did it and got better. They brought back another version and then had him revert.
* ''Franchise/{{Superman}}''
** SelfDemonstrating/LexLuthor started out as a minor if powerful villain, with only two comic appearances in the first year he was created. Superman's original arch-nemesis was intended to be the now largely forgotten Ultrahumanite.
** Though not a character, Kryptonite was first introduced in [[Radio/TheAdventuresOfSuperman the radio series]]. This AchillesHeel became a defining element of the Superman mythos. (Something called "K-Metal", which amounted to the same thing as Kryptonite, figured in a comic book script well before the radio show, but the script was [[WhatCouldHaveBeen never published]] because [[StatusQuoIsGod Lois Lane found out Superman's identity]].)
* If you were to watch any modern incarnation of the ''Franchise/TeenageMutantNinjaTurtles'', you would think arch-ninja The Shredder is the end-all-be-all of Turtles baddies. Originally, though? He died in the very first issue of the original comic, and was later brought back for a handful of issues--as a clone--only to be killed off again soon after, never to return.
* The Iron Major became a popular recurring villain for Comicbook/SgtRock, despite dying in his first appearance.
* SelfDemonstrating/DoctorDoom is this to the ComicBook/FantasticFour; appearing in their fifth issue, he took over their second annual, getting a DeathByOriginStory background for him and his parents, and has since then had his own book, own team-up series, and antagonized most of the Marvel [[TheVerse verse]] by power hoarding {{MacGuffin}}s and being TheChessmaster MagnificentBastard with PoweredArmor. Lampshaded in Doom's third appearance. Creator/StanLee and Creator/JackKirby spend some time discussing how good of a villain Doom wound up unexpectedly being and lament killing him off so fast. Doom promptly storms in, very much alive, and berates them for doing the same.
* The Angel gang in ''ComicBook/JudgeDredd'' were introduced as villains of the arc, and one by one were killed by Dredd as the "Judge Child" saga progressed. However, fan response was so positive that Mean was ''brought BackFromTheDead'', in one of the exceedingly few occasions that Tharg's rule against resurrections has been ignored. Mean has since become one of the iconic characters of the series.
* In the ComicBook/DisneyDucksComicUniverse, Flintheart Glomgold started out as TheRival to Scrooge for the title of Richest Duck in the World. Flintheart only appeared in three stories by his creator Creator/CarlBarks, but by his third appearance, he had ascended to Scrooge's EvilCounterpart and was one of the few villains to demonstrate [[ItsPersonal murderous intent]] against Scrooge and his nephews. The Second Richest Duck in the World was mostly forgotten for the next twenty years, until Don Rosa reintroduced him in "Son of the Sun". Comics, the cartoon series ''WesternAnimation/DuckTales'', and video games have since portrayed Flintheart as a step above Scrooge's usual villains to the point of being his ArchEnemy. Another breakout villain for Scrooge would be [[CorruptCorporateExecutive John D. Rockerduck]]. He was originally a one-shot character created by Carl Barks, but for some reason Italian duck artists made him a recurring character decades later.
* The [[Comicbook/NormanOsborn Green Goblin]] was originally a fairly average Franchise/SpiderMan villain, with possibly the only thing which made him stand out being the fact that his identity wasn't revealed and he kept escaping. Then he found out Spider-Man's identity…. [[ComicBook/TheNightGwenStacyDied then he killed Gwen Stacy]]… He's also an unusual case in that he was dead for quite a long time by comic book standards, but after he was brought back he tends to have some hand in almost every major plot against Spider-Man.
** [[ComicBook/JMSSpiderMan Joe Straczynski's run]] has Morlun - he was an antagonist only in the first JMS story, but was the only one to be brought back, usually as a part of a big event, as [[KnightOfCerebus his mere presence shows things are getting serious]].
** {{Comicbook/Venom}}. While he wasn't intended to be just another regular villain (he was made debut in a double-sized 300th issue), neither Marvel nor its creator foresaw him becoming the most popular Spider-Man villain and being promoted to one of the "big three" along with the Green Goblin and Doc Ock. Its creator even had plans to kill him off, but his popularity prevented this.
** As a result of this, Venom's creator created ComicBook/{{Carnage}} in order to kill him off in his place. Once again his plans were foiled when his debut issues quickly sold out despite lack of marketing and the character went on to become extremely popular, rivaling even Venom's fame and causing a [[Comicbook/MaximumCarnage 14-issue crossover centered on him]] to follow.
* Bullseye for Comicbook/{{Daredevil}}. DD had a fairly extensive Rogues' Gallery, but it was considered a pretty poor one. Then Bullseye, the assassin who [[ImprobableAimingSkills never misses]] debuted in issue #131, 12 ''years'' after DD himself appeared, and the great rivalry was on.
* Early in his professional career, comic book writer/artist Jim Starlin was offered to write an issue of ComicBook/IronMan. Starlin didn't think his career would last very long, so he took the chance to introduce a couple of new characters for his one-off issue. One of those characters was the issue's villain, ComicBook/{{Thanos}}. Starlin would go on to write many more comic books, and Thanos would become one of the [[BigBad Biggest Bads]] in the Franchise/MarvelUniverse.
* ''ComicBook/MortadeloYFilemon'': Ibáñez made appear the rival organization ABUELA only once, as a one-time VillainOfTheWeek in "El plano de Alí Gu-sa-no". This didn't stop other writers to use it as the arch-enemy of the organization TIA.

[[folder:Films -- Animated]]
* ''Disney/SleepingBeauty'': Maleficent was, in [[Literature/SleepingBeauty the original story]], not that important to the actual story and only appears a few times. The Disney adaptation has made it so that now Maleficent is widely considered to be among [[EvilIsCool the coolest villains]] Disney has ever produced, and indisputably one of the most formidable, and has become one of the go to main villains for Disney whenever they do a serious crossover, such as in ''Franchise/KingdomHearts'' and ''Theatre/{{Fantasmic}}'' She also got [[{{Film/Maleficent}} her own movie.]]

[[folder:Films -- Live-Action]]
* ''Franchise/StarWars'':
** [[EnsembleDarkhorse/{{Film}} Boba Fett]]. Boba Fett's presence in the movies was… minimal, at best. But oooooh, has he become a staple of the Franchise/StarWarsExpandedUniverse. Much contention has been made over his survival after being ingested by the Sarlacc ([[Creator/GeorgeLucas Lucas]] [[WordOfGod says]] he died; Creator/DarkHorseComics along with most fans say he survived), but his popularity cannot be debated. Boba Fett is, to most fans, as integral to the plot as any other characters - in some respects, much more important and likable to the series as a whole. Lucas' opinion later shifted to "[[AscendedFanon Sure Why Not]]," and he actually considered adding in a scene of him surviving in the 2006 [=DVD=] of ''Return of the Jedi''. Tellingly, Boba has a bigger role as a little boy in ''Film/AttackOfTheClones'' than he did as an adult in the original trilogy.
** Darth Vader counts as well. Because he's become such an iconic character, it's easy to forget that he actually had a relatively minor role in [[Film/ANewHope the original 1977 film]]: he only had 9 minutes of screen time, he didn't have his famous theme music, he and Luke's father were clearly meant to be different people, and he spent most of the film as an enforcer for the real chief antagonist, Grand Moff Tarkin. It wasn't until ''Film/TheEmpireStrikesBack'' dropped [[LukeIAmYourFather a certain revelation about Luke's parentage]] that he became the trilogy's main villain, with Luke's battle with him (and his eventual redemption) becoming a crux of the series.
* Agent Smith from ''Film/TheMatrix'' was originally supposed to be a StarterVillain, but due to his popularity with fans he was brought back and incorporated in the storyline of the [[TwoPartTrilogy next two films]] as the main antagonist.
* Pinhead of the ''Franchise/{{Hellraiser}}'' series was originally just one of the group of monsters in the original ''Film/{{Hellraiser}}''. [[spoiler:He was even killed off in ''Film/HellboundHellraiserII''.]] But Creator/DougBradley's portrayal of him made him very popular with the fans, and Pinhead today is the de facto villain of the series, and its mascot.
* Jason Voorhees in the original ''Film/FridayThe13th1980'' was [[spoiler:just a dead RedHerring to his mother, the real killer of the film]]. Then, it was decided to bring him back in [[Film/FridayThe13thPart2 the sequel]]. By the end of the eighties, Jason had become a pop culture icon.
* Khan from ''Franchise/StarTrek'' started out as just another VillainOfTheWeek for Kirk to defeat. He got to return in ''[[Film/StarTrekIITheWrathOfKhan The Wrath of Khan]]'' as one of the series' most notable villains. [[spoiler: He even got to show up in ''Film/StarTrekIntoDarkness'' as [[BigBadEnsemble one of the main villains.]]]]
* Though the first three ''Literature/JohnCarterOfMars'' novels form a loose trilogy, they don't really have a single BigBad- the closest thing would be [[PathOfInspiration the Holy Therns]], but they don't show up until the second book, and their leader Matai Shang doesn't put in a personal appearance until the third. For [[Film/JohnCarter the film adaptation]], both the Therns in general and Matai Shang in particular are {{Arc Weld|ing}}ed into the first novel's basic plot, with the intention of making him the unquestionable BigBad of the potential franchise.
* Three Finger from the ''Film/WrongTurn'' series, the only character to appear in all five films. In the original, he and his brothers had about the same amount of screentime, and Saw Tooth appeared to be the leader of the group.
* In the Franchise/MarvelCinematicUniverse, Comicbook/{{Loki}} played by Creator/TomHiddleston has exploded in popularity as the villain in both {{Film/Thor}} and ''Film/TheAvengers'', becoming probably the most popular character in the universe after Tony Stark.
* The ''Franchise/{{Godzilla}}'' films first had King Ghidorah in this role. Originally brought for a movie to give Godzilla and Rodan a villain to work together against, his popularity led to him becoming Toho's most used monster aside from Godzilla himself, even appearing as villain to Mothra. The second one was Mechagodzilla. Originally just done using the idea of a robotic EvilKnockoff to Godzilla Toho had done with King Kong, Mechagodzilla providing [[KnightOfCerebus a much more serious threat than anything Godzilla had fought in years]] led to it becoming his most popular and iconic enemy aside from King Ghidorah, and since then every new Godzilla film series has included a version of it.
* The Tremor family from ''Film/SmokinAces'' were all killed off in the first movie, but they proved so popular that the second film became a prequel just so they could show up again.
* Jaws, the famed henchman with the steel teeth from ''Franchise/JamesBond''. He was originally supposed to die at the end of ''Film/TheSpyWhoLovedMe'', but Richard Kiel's acting made him so likable that they changed the ending so that he survived when it turned out that the test audiences loved him. He returned in ''Film/{{Moonraker}}'', becoming one of the rare villains to appear in multiple Bond films, and [[WhatCouldHaveBeen would have returned in]] ''Film/ForYourEyesOnly'' too had the producers not ultimately decided to go for a more realistic Bond film. He has since become one of the most iconic villains in the franchise, appearing in multiple video games and even the ''WesternAnimation/JamesBondJr'' cartoon, always as an ImplacableMan that Bond must defeat through creative means.

* Professor James Moriarty, created by Sir Creator/ArthurConanDoyle to be a one-time opponent of Literature/SherlockHolmes, and to bring about Holmes' demise. In fact, Moriarty was only given more than a passing mention ''three times'' in Doyle's work - the story where he appeared, and apparently killed Holmes; and the following story, which brought Holmes BackFromTheDead, and in this it's only Moriarty's men; a third story, written much later but set earlier, uses him as a brief DiabolusExMachina. ''Every'' author, director, fan, etc. afterwards, though, has made Moriarty ''the'' villain of Sherlock Holmes, lifting him to the point of mythical status among literary characters; to the modern viewer, it's inconceivable to have an original Holmes movie or television series with original Holmes mysteries without having Moriarty as the central, most important villain.
** He is now so integral to the mythos that a subplot of the first episode of ''Series/{{Sherlock}}'', revolving around the mysterious and vaguely threatening figure who tries to get Watson to spy on Holmes, only works because the audience ''expects'' this to be Moriarty [[spoiler: and thus be surprised when it turns out to be Mycroft Holmes]]. A later episode of the same series reveals that all Sherlock's cases so far [[HijackedByGanon were connected to Moriarty's shemes.]]
** Another "villain" to become central to the Holmes Universe (i.e. original canon ''and'' adaptations), despite her one appearance, is Irene Adler, who is the ''only'' woman to ''ever'' outwit Holmes. In Doyle's stories, he does make a few fleeting mentions of her as the only person whom Holmes never beat - though hardly as many as one might be led to expect by adaptations
** {{Fanon}} has retconned both Moriarty and Irene into the Holmes mythos. There is now a timeline of cases where Holmes clashed with Moriarty's organization, and it's a popular theme in homages and pastiches that Sherlock and Irene had a tryst during Holmes's absence after Reichenbach.
** Colonel Sebastian Moran, Moriarty's [[TheDragon right-hand man]]. The story that brought about Holmes's resurrection established that he was there when Holmes killed Moriarty, even spontaneously attempting to finish the job, then proceeds to become a Breakout Villain himself. One of the few characters that gets mentioned in several stories, despite only appearing in one, to the point where he's sometimes Watson's full blown EvilCounterpart.
** ''Series/{{Elementary}}'' does us two for one. Holmes' season one character arc and backstory was hinged on Irene Adler, and how he spiralled into drugs after she was killed by Moriarty. They became two very important [[TheGhost ghost characters]] for most of the season, [[spoiler: until the finale, when it's revealed that they are one and the same. Moriarty forged Irene's persona to distract Holmes, then bring about his downfall because he foiled her plans.]]
* ''KingArthur'': Mordred. In the early mentions of KingArthur in Welsh mythology, Arthur was slain by Medraut, later to be known as Mordred. However, Medraut's importance in the mythos as a whole was almost non-existent, save for that he killed King Arthur. Other villains had come and gone, and it seemed that Mordred was intended to just be another, though the only one who finally got lucky (although Arthur slew him in the same action, so his luck is debatable). Ask anyone in modern times, however, who is ''the'' villain of the story of King Arthur, and the answer you will get is "Mordred" almost all the time (though Morgan Le Fay is another name that also comes up quite frequently, and is, coincidentally, another example of this trope). Mordred has become so integrated into the mythos of Arthur that it is unheard of to ''not'' include him in any story involving Camelot.
** Modern depictions of Mordred usually bump him up to being King Arthur's son with Morgan, which has a number of neat effects. First of all, it ups his status from being a random evil knight into LukeYouAreMyFather. Second, it gives him an actual motivation - he wants to be recognized as the rightful heir but Arthur refuses. Third, it makes Arthur the architect of his own demise, directly. Fourth, it ties him in with Morgan Le Fay, the other popular Moriarty of the series, so everything's wrapped up in a neat little package.
*** This is TheThemeParkVersion by way of the OneSteveLimit. Originally, Mordred's mother was Morgan's sister Morgause, which ends up giving him a supporting cast in the form of his (half-)brothers at court - Gawaine, Gareth, Gaheris, and Agravaine. In Malory, at least, they're a bit of a FiveManBand. The earliest mention of Mordred is a reference to "The Battle of Camlann" where "Arthur and Medraut died". From the context (or lack of same), it's not even clear that they were on opposite sides!
** The Welsh Triads include Mordred in a list of ''heroes''. The first unambiguous mention of Villain!Mordred is in Geoffrey of Monmouth's ''Literature/HistoriaRegumBritanniae'' (1100s). From there, Mordred got steadily more villainous: in Geoffrey he only speaks twice, in the Alliterative ''Morte Arthure'' (early 1300s) he's an angsty WorthyOpponent, in the Stanzaic ''Morte'' (late 1300s) he's distinctly worse, and by Malory's ''Literature/MorteDarthur'' (1470s) he's all the way into ForTheEvulz. As Malory's is the only version most non-medievalists have read, that's the characterization that held.
** In the end, calling Mordred a "breakout villain" is strange, to say the least. You go back far enough, and he isn't even a villain, but ever since Geoffrey brought him in his function has been constant: he kills Arthur. And, interestingly, that's ''all'' he does in most versions. He spends the entirety of Malory hanging around the background, getting constantly mentioned but never doing anything. A byproduct of the fact that there are no "tales of Sir Mordred" since all he ever did was stab his uncle and/or father in the back and try to force Guinevere into marriage.
*** Post Malory, however, there are some works that try to make Mordred into a full on BigBad for the whole of King Arthur's story.
*** As stated before, Morgan La Fey is another example. She goes from healer who preserves Arthur's immortality, to minor level evil witch, to full blown BigBad in a great many modern takes on King Arthur.
* ''Literature/TheLordOfTheRings'' - Sauron originated as a relatively minor villain from the earliest version of the legend of Beren and Lúthien, and the proto-Sauron was a giant {{cat|sAreMean}}. The character subsequently morphed into the EvilSorcerer Thu, and from there into the demonic being known from ''Literature/TheLordOfTheRings''. In the process, he got promoted from one-shot villain to the GodOfEvil's [[TheDragon Dragon]] to the DragonAscendant and BigBad of the most well-known part of the mythology and the second most significant villain in the Middle-earth {{Verse}}.
* ''Literature/TheWonderfulWizardOfOz'' - The Wicked Witch of the West, thanks to the popularity of [[Film/TheWizardOfOz the classic film]], has become the most recognizable of Oz's villains and the BigBad of most adaptations of the Oz series (i.e. the 1980s cartoon). In the original novels she only appeared in one chapter in the middle of the first book, during which she was KilledOffForReal; the closest thing [[Literature/LandOfOz the Oz books]] have to a BigBad is actually the Nome King, who appeared in several books to cause trouble for the land of Oz. In particular, [[AdaptationDisplacement it's the 1939 film version everyone remembers]]. This is noteworthy because that adaptation actually changed the character quite a bit -The book Witch wasn't green, didn't ride a broomstick, and was not the Wicked Witch of the East's sister (though they were allied). But [[LostInImitation the success of the film has caused those traits to be adopted by many subsequent adaptations]], even ones that are ostensibly based on the books.
* ''Literature/AliceInWonderland'':
** The Queen of Hearts only appeared in the last third of the first ''Alice'' book and wasn't really as much a villain as she was a temperamental yet comic battleaxe, whose executions were never really carried out. However, ''Alice'' spinoffs like ''VideoGane/AmericanMcGeesAlice'', ''Literature/TheLookingGlassWars'' and the 2010 Creator/TimBurton [[Film/AliceInWonderland film]] have made her the main villain, transforming her into an evil dictator who rules Wonderland with an iron fist and Alice's greatest nemesis. Oddly adaptations will also often combine the distinct, if thematically similar, Queen of Hearts and Red Queen characters into one when doing this.
** Likewise, The Jabberwock, who only appeared in a poem in ''Through the Looking Glass'' where he was quickly killed, has become a significant villain in things like the aforementioned ''VideoGame/AmericanMcGeesAlice'' and Burton film, as well as a television adaptation in which it stalks Alice throughout.
* Guy of Gisbourne originally appeared only once in the ''RobinHood'' legend as a bounty hunter who gave Robin an extremely tough fight but was ultimately defeated and killed. He has overtime been elevated to TheDragon or even BigBad status in retellings.
* ''Franchise/ConanTheBarbarian'': Thoth-Amon makes only a passing appearance in a few stories, but both comic adaptations make him Conan's ArchEnemy.
* ''Literature/ArtemisFowl'': Opal Koboi was originally just part of a BigBadDuumvirate with Briar Cudgeon (an antagonist, but not really the main villain of the first book) in the second book. Then she returned in the fourth book, [[spoiler: killing Holly Short's superior.]]. And was revealed to be the BigBad of the [[spoiler: sixth and eighth book]].
* [[DemonicDummy Slappy]] of the ''{{Literature/Goosebumps}}'' series was a minor character in the original "Night Of The Living Dummy". [[spoiler:He wasn't even the actual villain of the book.]] Despite that, he was brought back for a sequel book, and took off as the series standout villain from there.
* [[Literature/FactionParadox Faction Paradox]] from the [[Literature/EighthDoctorAdventures Eighth Doctor Adventures]] first appeared in "Alien Bodies", in which they were just one of the villains. They become the closest things to the BigBad for much of the series and eventually got a spin-off, though set in an alternate continuity.

[[folder:Live-Action TV]]
* In ''Series/LawAndOrderCriminalIntent'' we have Nicole Wallace, AKA That Evil Aussie Chick. Now, this being a crime show, she doesn't get that many appearances, but if you can outwit [[CrazyAwesome Goren]]...
* ''Series/DoctorWho'': The Daleks: Despite challenging the TARDIS for the title of the most iconic element of ''Doctor Who'', they were created in defiance of co-creator Creator/SydneyNewman's insistence on writing a non-traditional ScienceFiction series which would avoid [[AliensAndMonsters Bug-Eyed Monsters]]. This explains why they ''died'' at the end of their first story with no hint given that they might possibly return. Now these motorized pepper-pots have had more than twenty appearances and posed a threat to the Doctor exceeded only by other Time Lords and similarly {{Sufficiently Advanced Alien}}s.
** In turn, Davros, the creator of the Daleks, made such an impression in "Genesis of the Daleks," that all the remaining Dalek stories in the original series are basically Davros ones to some degree with the Daleks largely reduced to his flunkies and rivals. This is arguably a case of this trope not working in his favor as using Davros so much turned him into a huge BaseBreaker from overexposure.
*** A lesser but still relevant example: The Autons. They appeared twice, in 1970 and 1971, but are still remembered as one of the Doctor's iconic villains. When the series was revived in 2005, Creator/RussellTDavies and co. were deliberating what classic Doctor Who-monster would be used in the first new episode to relaunch the series. The Autons were given that honor.
** The new series has the Weeping Angels, whose first appearance didn't even have them fighting the Doctor directly, but after subsequent appearances they're on their way to joining the show's showcase of most iconic monsters.
** Another lesser version is the Zygons, who only made one appearance in the Classic Series. Despite this they are among the most popular Doctor Who monsters and ended up being the main villains for most of the 50th anniversary special.
* ''Series/{{Lost}}''
** Benjamin Linus, or rather actor Michael Emerson, was originally scheduled for a three episode stint in Season 2. His performance won the producers' everlasting affection and it was expanded to the rest of the season, and then into a regular in Season 3. If this isn't reason enough to include him, in Season 4 one of his fake aliases happens ''to be'' Moriarty.
** Dean Moriarty, though, making this an ''On the Road'' reference, as well as a nod to ''Sherlock Holmes''. (The character from ''On The Road'' was named as a reference to the Holmes villain, it still works as a reference to both.)
* Sigfried from ''Series/GetSmart'' was originally meant to be a one-time villain, but then popped up again a few times, and is now considered the main villain of the series, even appearing (well, InNameOnly) in [[Film/GetSmart the 2008 feature film adaptation]].
* Cavil on ''Series/{{Battlestar Galactica|Reimagined}}''. In his original appearance, he actually seemed to be one of the nicer Cylons. Turns out he was lying about not supporting the genocide and was its main instigator. Then it turns out that [[spoiler: one of the Cavils introduced was a nice Cylon not supporting the genocide, and the other Cavils introduced was the mastermind. Alas, The Plan...]]
* Scorpius from ''Series/{{Farscape}}'' was ''supposed'' to be a one-shot first-season villain but the performance was so effective that he returned and quickly usurped the then-BigBad.
* ''Series/BuffyTheVampireSlayer''
** Spike. Originally meant to be a one-season villain, and a DiscOneFinalBoss at that, [[EnsembleDarkhorse/LiveActionTV he quickly went on to be one of the show's most popular characters]], converting to full-fledged AntiHero by the fifth season, and continuing into ''Series/{{Angel}}'' after the series ended.
** Also, [[UltimateEvil the First Evil]] was originally set to be the BiggerBad--evil, but so vast that it wouldn't really show up. It eventually returned as the BigBad of the final season due to its ability to appear as all the other dead (and undead) villains from seasons past.
* ''Series/StarTrekDeepSpaceNine'': Although Gul Dukat appeared in the pilot episode, he was never intended to be a recurring character...but Marc Alaimo just played him so ''well''.
* ''Series/KnightRider'': [[BetaTestBaddie K.A.R.R.]] was originally a one-episode villain. He was introduced as K.I.T.T.'s EvilCounterpart and ultimately destroyed at the end of the episode. He was brought back in a second episode, "K.I.T.T. vs. K.A.R.R.", due to his popularity. Despite only appearing in two episodes, he's widely remembered as the heroes' ArchEnemy and plays a prominent role in both the video game and the recent reboot of the series.
* Murdoc the MasterOfDisguise assassin on ''Series/MacGyver''. Originally a one-episode villain, his use of creative schemes and {{deathtrap}}s made him a good foil for master-of-improvisation MacGyver himself, so they kept bringing him back about once a season (due to his NeverFoundTheBody and StayingAlive tendencies), and he's now remembered as [=MacGyver=]'s ArchEnemy.
* Sylar on ''Series/{{Heroes}}'' was originally planned to be the series' StarterVillain, who would be KilledOffForReal at the end of the first season. However, due to the character's popularity with fans, he was made into a main character and "The Face of Evil" for the series, to the point that every following BigBad ends up getting [[HijackedByGanon Hijacked By Sylar]] in their season's finale.
* In ''Series/{{Sliders}}'', the Kromaggs (an evil AlternateUniverse version of humanity that had evolved differently) eventually become this. Unfortunately it also marks the point where they become the MalignantPlotTumor, since the show's original WalkingTheEarth appeal had to be down toned to make place for more action scenes.
* Barabas, the Demon of Fear, was a MonsterOfTheWeek villain who appeared in the 13th episode of ''Series/{{Charmed}}''. He proved popular enough that the writers ended up bringing him back several times (about once every other season). He never became a seasonal BigBad, but is probably the show's most frequently-occurring nemesis right behind the actual Big Bads.
* ''Series/{{Smallville}}'': [[TheChessmaster Lionel]] [[ManipulativeBastard Luthor]], [[LonelyRichKid Lex's]] CorruptCorporateExecutive AbusiveDad was originally meant to appear in only a few episodes of Season 1 as a way of making [[MadDictatorsHandsomeSon Lex's]] FreudianExcuse seem more poignant. Creator/JohnGlover's performance was excellent, however, and the fandom embraced the [[FanNickname Magnificent You-Know-What]] as a LoveToHate character of the first degree. Lionel was written into Season 2 as a major antagonist and RecurringCharacter, and became the BigBad of Season 3. In the process he gained new dimensions to his character and his own FreudianExcuse becoming an EvenEvilHasStandards ArchnemesisDad who was himself the product of AbusiveParents. He was later [[DemonicPossession possessed]] by Jor-El and made a HeelFaceTurn, becoming a dark {{Mentor|s}} figure to [[TheHero Clark]]. KilledOffForReal in Season 7 by [[SelfMadeOrphan Lex]], Glover and Lionel returned to the show in Season 10 as [[AlternateUniverse Earth-2]] Lionel, an [[EvilTwin Eviler Twin]] of our Lionel, who was TheHeavy for most of the last part of the show. In some ways Lionel, and not Lex as was originally intended, became ''Smallville'''s defining villain.\\
Lionel, and Glover's portrayal of him, resonated so well that he was written into the comics as Lex Luthor's canonical (and deceased) father. While Lex had obviously always had a (deceased by the time of the "present day") father, this character had never had a consistent name or physical appearance and usually had no importance. But ever since ''Smallville'', Lex's father is explicitly named "Lionel Luthor" and flashback scenes have depicted him as looking very similar to actor Creator/JohnGlover. A zombiefied, Black Lantern version of Lionel even showed up for revenge against Lex in ''ComicBook/BlackestNight''.
* Emilia Fox as Morgause from ''Series/{{Merlin}}'' was only supposed to be around for a couple of episodes, but ended up being so integral to the episodes she featured in that the writers kept her around for longer.
* Klaus from ''Series/TheVampireDiaries'' quickly became this despite the fact his influence was originally not going stretch far into season 3, much less into season 4. However his character as well as the other Originals (Elijah gets a special mention as someone who was going to die within one episode), became very popular in addition to the writers just loving writing for them. Klaus is so popular he may in fact get his own spin off.
* On ''Series/{{Batman}}'' Comicbook/TheRiddler quickly came to be one of the Dynamic Duo's most popular adversaries, likely because of Frank Gorshin's amazing performance as the character.
* On ''Series/StargateSG1'', Ba'al is obviously intended to be a villain of the week, but Cliff Simon's performance became a fan-favorite, particularly in later appearances where his character becomes DangerouslyGenreSavvy.
* On ''Series/ICarly'', Neville was originally going to be a one-shot villain, but he had since become a recurring villain out and the gang's ArchEnemy. Creator/DanSchneider even called him TheJoker to Carly's {{Batman}}.
* On ''{{Series/Alias}}'', Mr. Sark was originally just a gofer for the Season 1 BigBad, [[TheSpook The Man]]. He was such a hit with the fans that he became TheDragon in Season 2, then became the DragonAscendant to [[BigBadDuumvirate share]] the Big Bad role in Season 3, went back to being the Dragon in Season 5, and, in fact, eventually managed to [[spoiler:be the ''only'' recurring villain on the show to make it all the way through the finale alive and free]].
* Dr. Miguelito Loveless debuted in the third episode of ''Series/TheWildWildWest'' and ended up getting captured. But he made such a memorable impression (and his actor, Michael Dunn was [[MeanCharacterNiceActor good friends with]] lead Robert Conrad in RealLife) that he'd turn up again and again (his second episode would be the only other time he'd get captured) to become Jim West's undisputed archenemy.
* ''Series/{{Supernatural}}'': [[MagnificentBastard Crowley]] was originally just a minor character aiding the Winchesters against [[{{Satan}} Lucifer]] in what Eric Kripke intended to be the final season. After it [[PostScriptSeason continued beyond that]], he was popular enough to come back and he's since become the show's most recurring and recognizable antagonist, eventually being promoted from recurring character to main cast in Season 10.

[[folder:Tabletop Games]]
* ''TabletopGame/MagicTheGathering'':
** When [[GodOfEvil Yawgmoth]] and [[ANaziByAnyOtherName the other Phyrexians]] first appeared, they were barely a footnote in the flavor of the Antiquities expansion; eventually, they morphed into the centerpiece of Magic's RoguesGallery. After Yawgmoth's defeat, the Phyrexians made a comeback in the ''Scars of Mirridon'' block.
** [[TheChessmaster Nicol Bolas]] was one of the five elder dragons in ''Legends''. Due to his card having a more powerful and unique mechanic than the others, he was reprinted 12 years later in ''Time Spiral'' and was one of many characters from the past to appear in its novels. While most of the old planeswalkers were either killed off or depowered in those novels, Bolas remained as a planeswalker. He appears again in the ''Alara'' block, and has since taken over the position of BigBad from the Phyrexians.

* ''Franchise/SuperMarioBros'':
** Bowser. Before ''VideoGame/SuperMarioBros1'', the portly plumber tangled with a lot of nasty foes. VideoGame/DonkeyKong, Foreman Spike, and random unorganized critters (though some did look similar to Koopas). But once ''Super Mario Bros.'' hit the scene, it was Mario's defining moment, and from that day forth, the Koopa troop and its fearless leader would be his most prominent nemesis. This seems even more dramatic in America, where Bowser was in fact absent for [[VideoGame/SuperMarioBros2 a game]] before making a triumphant reappearance in ''VideoGame/SuperMarioBros3''. In this case it was the unforeseen popularity of the game that caused Bowser to become a Breakout Villain.
** VideoGame/{{Wario|Land}}. The ''VideoGame/SuperMarioLand'' games felt like {{Gaiden Game}}s to the main franchise, and then part 2 featured this fellow, and the next one starred him, and he turned AntiHero. Since then he's been a mainstay of the Mario franchise.
* In the original PlayStation version of ''VideoGame/ResidentEvil1'', Albert Wesker was just a standard horror movie stock character (the obligatory traitor who gets eaten by the monster in the end, Paul Rieser's character from ''Aliens''). However, following his return in ''VideoGame/ResidentEvilCodeVeronica'', he managed to pretty quickly be built up to be the BigBad of the entire series over the course of the following decade up until his last appearance in ''VideoGame/ResidentEvil5''.
* Revolver Ocelot in the original ''VideoGame/MetalGearSolid'' was notable for being the sole surviving member of the renegade FOX-HOUND unit by the end of the story and a mole under the service of Solidus Snake, although there was not much to suggest that he was anything other than a double agent. Each subsequent entry in the series would reveal more about Ocelot's past and motives, having him shift from one allegiance to the next and outliving the main antagonist of each game until becoming the main antagonist himself in ''VideoGame/MetalGearSolid4GunsOfThePatriots''.
* ''VideoGame/{{Warcraft}}'': Sargeras started out as little more than a footnote in the lore, as a SealedEvilInACan demon lord whose powers [[EvilSorcerer Gul'dan]] tried to harness. The revelations of his origins as a fallen [[PhysicalGod Titan]] and creator of the [[TheLegionsOfHell Burning Legion]] elevated him to BiggerBad of the ''entire franchise''.
** Also the OldGods (a race of {{Eldritch Abomination}}s), originally a tangential source of the mythos based on the CthulhuMythos, they were used to add some creepy side stories used in the expanded WorldOfWarcraft storyline, and also used as DiscOneFinalBoss for the original version of the game (pre-expansion), the Old Gods consistantly appear as the ultimate source of all evil, to the point it has a become a RunningGag to blame things on them
*** [[MadGod Sargeras]], [[GodOfEvil founder]] of the [[TheLegionsOfHell Burning Legion]]? Went mad fighting the Old Gods. Weird primal deities worshipped by troll witch doctors? Totally Old Gods. Elementals Lords? Servants of the Old Gods. The Lich King? His necromantic powers all derive from the Old Gods. [[OurDragonsAreDifferent Deathwing]]? Pawn of the Old Gods. War of the ancients? Masterminded by the Old Gods. Creepy fairy circles in Tyrisfal? Probably the Old Gods. Negative emotions buried beneath the earth by an Ancient Emperor that come to life? Actually remnants of dead OldGods
*** Flesh races supplanting the rock and metal older races? [[CursedWithAwesome Blame the Curse of Flesh]] inflicted on the old races by Yogg-Saron.
* [[MadScientist Wilhelm]] [[NamesToRunAwayFromReallyFast "Deathshead"]] [[RetCon Strauss/Strasse]] of the [[{{Ghostapo}} SS Paranormal Division]] returns as the eventual BigBad in ''VideoGame/{{Wolfenstein 2009}}'', mainly due to his status as being the sole surviving Nazi of any prominence in ''VideoGame/ReturnToCastleWolfenstein'' besides [[DoomedByCanon Himmler]]. He's even more prominent in ''VideoGame/WolfensteinTheNewOrder'', being the primary source of the Nazis' [[StupidJetpackHitler mechs and other super science]].
* Bishop Ladja of ''VideoGame/DragonQuestV''. In the original SNES game, while he did have some presence in the plot, he was ultimately a minor villain who showed only a mild evil and [[spoiler:dies less then halfway through the game]]. The DS remake propels him into this, giving him a unique appearance, replacing King Korol with him as TheDragon, giving him much more screentime.
* SHODAN was so much of a standout villain in the first ''VideoGame/SystemShock'', that she was brought back for the second, where she became one of the most legendary villains in gaming history.
* Vergil, Dante's {{Aloof|BigBrother}} [[EvilTwin Elder Twin]], from ''VideoGame/DevilMayCry''. In his first appearance, he was simply [[spoiler:a BrainwashedAndCrazy servant of the game's BigBad known as Nelo Angelo]], although he made a good impression by serving as a [[WakeUpCallBoss challenging]] MirrorBoss [[RecurringBoss several times over]]. Then, he reappeared in ''[=DMC3=]'' (a prequel chronicling some of Dante's backstory and early demon-hunting days), giving players a glimpse of his more complex character quirks and motivations, revamping him into an even more challenging opponent that stands in Dante's way, and [[spoiler:giving him a somewhat pitiable send-off of sorts]]. Needless to say, this not only made Vergil the most recurring boss in the series (with a total of 6-7 battles), but cemented him as the most recognizable villain as well. As such, Vergil joined the lineup of ''[[UpdatedRerelease Ultimate]] VideoGame/MarvelVsCapcom3'' alongside Dante and Trish (herself something of a BreakoutCharacter), much to the delight of ''DMC'' fans.
* Ridley, from ''Franchise/{{Metroid}}'' was originally just TheDragon ([[OurDragonsAreDifferent literally]]) in [[VideoGame/{{Metroid1}} the original NES game]]. Nowadays he's Samus' ArchEnemy due to his involvement in her past when he murdered her parents and [[JokerImmunity his refusal to stay dead.]] [[AwesomeBosses/{{Metroid}} His consistently awesome boss fights might also have something to do with it.]]
* The Materials in the ''VideoGame/MagicalGirlLyricalNanohaAsPortable'' games were originally one-dimensional [[EldritchAbomination Darkness of the Book of Darkness]]-based EvilTwin copies of the three Aces, and were unceremoniously destroyed by the end of the first game, ''The Battle of Aces''. Except it turns out that the fans liked the Materials, so they were revived in the sequel, ''The Gears of Destiny'', and had the game revolve around them, expanding their personalities, backstories, and importance. Oh, and they also got an [[ official manga with them in the starring role]]. And they return in another AlternateContinuity as the main foreign rivals team of the Card Game-focused ''Magical Girl Lyrical Nanoha INNOCENT''. Not bad for LicensedGame SpinOff villains who were supposed to just show up and get killed on their first appearance.
* ''Franchise/SonicTheHedgehog'': Similar to Ridley, Metal Sonic was originally just TheDragon to Dr. Eggman, appearing only as a boss in Sonic CD. Eventually, his popularity skyrocketed to the point where [[spoiler: he was made the BigBad of ''VideoGame/SonicHeroes''.]] He's generally considered the second most prominent villain after Eggman himself.
* ''Franchise/KingdomHearts''
** Both Axel and Xigbar have had their roles expanded since their debut game thanks to their popularity. The difference is Axel undergoes a HeelFaceTurn and becomes an anti hero, then later a straight hero [[spoiler: with his own keyblade no less.]] Xigbar turns out to be the main Dragon for Xehanort and [[spoiler: as of 3D shares BigBad status with him as one of his 13 vessels]].
** To a lesser extent, Chernabog was so well received (being an awesome boss to fight, and having his own theme from ''Disney/{{Fantasia}}'', ''Music/NightOnBaldMountain'', playing in the background) that he came back as a boss fight for Riku in ''Dream Drop Distance''. His appearance is very close to an heartless, and he has the privilege to be one of the only enemies in the [=KHverse=] to not have a entry in Jiminy's journal, which only reinforces his aura and mystery.
* From the ''VideoGame/SilentHill'' series, Pyramid Head from the second game left such an impression on everyone that he's often seen as the series' mascot, of sorts. Despite the original [[EnemyWithout nature of his character]], he appeared in a somewhat different form in ''Silent Hill: Homecoming'', and appeared in both of the film adaptations of the games.

* In ''Webcomic/TheOrderOfTheStick,'' [[EvilTwin Nale]] was the only member of [[ThePsychoRangers the Linear Guild]] originally slated to escape from the first battle with the heroes. However, fans really liked [[PsychopathicManchild Thog]], so [[FanNickname the Giant]] decided to spare him and, while he was at it, [[HornyDevils Sabine]] as well, developing her and Nale's relationship into a case of UnholyMatrimony.
** Similarly, [[TheDragon Redcloak]] was originally going to be killed off fairly early on (his name was even envisioned as a pun on RedShirt). Instead, he ended up surviving and being fleshed out, becoming one of the most complex characters in the story.
** This trope is a key facet in [[spoiler: Tarquin]]'s XanatosGambit involving Elan. It's his contingency in case his EvilEmpire plot is toppled. The legend of the hero who defeats him will serve to spread his own legend and inspire generations of new {{Evil Overlord}}s to follow in his footsteps. As he puts it, "If I win, I get to be a king. If I lose, I get to be a LEGEND!"

[[folder:Western Animation]]
* [[VillainousHarlequin Harley Quinn]], everyone's favorite Hench Wench from ''WesternAnimation/BatmanTheAnimatedSeries''. She was originally invented as a one-shot female henchmen to leap out of Commissioner Gordon's cake (The censors allowed [[EvilClown The Joker]] to do it instead), and an overwhelming fan response turned her into a recurring villain and a CanonImmigrant into the comics. She even went on to be one of the few villains to [[BatmanGambit Out-Batman Gambit]] Batman himself and come ''this close'' to actually killing him.
* ''WesternAnimation/KimPossible''
** Shego was originally "just a henchman" to Dr. Drakken, but later developed into a [[HypercompetentSidekick competent]] but [[BrilliantButLazy unambitious]] villain who entertained herself (and the audience) with her [[DeadpanSnarker incessant verbal jabs]] at [[PointyHairedBoss Drakken]] and [[IShallTauntYou Kim]]. Drakken's own standing has curiously enough has also benefited from her popularity: even though he gets out-shined by his own assistant on the popularity polls it was thanks to this dynamic that he became the second most important villain in the series.
** Monkey Fist was originally just a crazed monkey themed villain who happened to be one of the few villains Ron Stoppable could actually face. Over time, as Mystical Monkey Power became more prominent, so did Monkey Fist (effectively becoming Ron's ArchEnemy).
* In the original Mirage Comics version of the ''ComicBook/{{Teenage Mutant Ninja Turtles|Mirage}}'', the Shredder was actually a fairly lackluster StarterVillain who managed to get himself KilledOffForReal at the end of the very first issue. In later issues a colony of sentient worms would take up the mantle of The Shredder (it's a long story), but even they only appeared in a few issues and played a rather minor role in the comics plotline. However, [[WesternAnimation/TeenageMutantNinjaTurtles1987 the 1980's cartoon adaptation]] made him the BigBad, and he's been the Turtles' ArchEnemy in every future adaptation of the series ever since. In ''WesternAnimation/TurtlesForever'' Mirage Shredder shows up for about 10 seconds before he's knocked off a building by the [[LethalJokeCharacter 1980's Turtles.]]
* On ''WesternAnimation/{{Gargoyles}}'' the [[EvilSorcerer Archmage]] was originally only supposed to be a [[MonsterOfTheWeek Villain Of The Week]], but creator Greg Weisman liked David Warner's voice acting so much he decided to bring him back, making him the villain of the three-part "Avalon" arc through a StableTimeLoop and a couple [[ArtifactOfDoom Artifacts of Doom]].
* Mad Stan from ''WesternAnimation/BatmanBeyond'' was originally a one-shot joke villain thrown in to make Terry miss his date with Dana. The fans [[LargeHam loved him]], and he eventually became a regular member of the RoguesGallery.
* Negaduck from ''WesternAnimation/DarkwingDuck''. After the Negaduck I episode, Tad Stones (the Show Runner) said he liked Negaduck and wanted him brought back for more episodes; this resulted in Negaduck II, who the fandom embraced as perhaps not just the most popular villain but the most popular ''character'' on the show, period. When [[Comicbook/DarkwingDuck the revival comic book]] came around, the writer has said that he intended to have a F.O.W.L. story for the second arc and a Negaduck story for the third arc, but sheer fan demand made him swap the order.
* In ''WesternAnimation/ThePowerpuffGirls'', [[ThePsychoRangers The Rowdyruff Boys]] were originally one-shot {{evil|Counterpart}} [[DistaffCounterpart spear]] counterparts of the titular heroines that got KilledOffForReal at the end of the episode. Fan popularity ensured that they were brought back several times.
* Plankton of ''WesternAnimation/SpongebobSquarepants'', while initially a recurring villain, was placed alongside many other antagonists or jerks the cast faced. As seasons passed, he got [[SpotlightStealingSquad more and more spotlight episodes]], and often acts as a VillainProtagonist in his appearances.
* ''WesternAnimation/TheDreamstone'', while Sgt Blob and his minions Frizz and Nug were always the consistant villains, they were merely mooks to the real BigBad Zordrak initially, with the story designed with Rufus as the intended main character initially. Within a short duration of episodes, both the heroes and Zordrak were DemotedToExtra with Blob's men usually acting as {{Villain Protagonist}}s. In later seasons Urpgor also gets larger roles and sometimes eclipsed even the other Urpney squad in screentime.
* Both Jack Spicer and Chase Young of ''WesternAnimation/XiaolinShowdown'' had astounding popularity, even more noticeable for Jack since in-show he was treated as barely more than a nuisance after the first season, but fans latched onto how comedic and unexpected he could be. Excluding Hannibal Roy Bean, just about all other villains ended up working for Jack or Chase at various points. Many fans even treat Jack and Chase as if they were the real stars of the show.