* Demona in ''WesternAnimation/{{Gargoyles}}''
* In ''WesternAnimation/{{Metalocalypse}}'', when Toki gets fed up with always being the child friendly one and then starts burning the lair with a flamethrower.
* Zuko from ''WesternAnimation/AvatarTheLastAirbender'' does a beautiful FaceHeelTurn in the season 2 finale. Actually, he does a FaceHeelTurn, then a HeelFaceTurn, then another FaceHeelTurn, then a few somersaults, ending with another HeelFaceTurn. Say that three times fast. His first FaceHeelTurn came when he was 12. An innocent, well-meaning boy gets half his face burned off by his ''loving'' father. After this, he hunts Aang ruthlessly for his "honor." His second, and most exemplary FaceHeelTurn, came at the second season finale. After starting fresh in Ba Sing Se, Zuko has to choose between his honor and his Uncle. After a blatant "I Hate You" speech, he attacks Aang and returns home a hero, at least until his final HeelFaceTurn.
** The series' sequel, ''WesternAnimation/TheLegendOfKorra'' gives us Tarrlok, a [[SmugSnake Smug Weasel-Snake]] who, at least, appeared to be willing to ShootTheDog and [[IDidWhatIHadToDo doing what he had to do]] to keep Republic City safe from the Equalists and BigBad Amon. In "When Extremes Meet," though, he [[TookALevelInJerkass takes a massive level in Jerkass]], arresting most of the new Team Avatar and a lot of innocent non-benders. When Korra confronts him about it, Tarrlok tries to tell Korra she's NotSoDifferent than him, but she rebuffs him, including rejecting Tarrlok's request to free Team Avatar if she works with him. Then Tarrlok [[PeoplePuppets bloodbends Korra]] and kidnaps her, telling her she'll never see Republic City again. [[spoiler:Not long after that, [[BigBad Amon]] kidnaps Tarrlok (inadvertently letting Korra escape). When Korra runs into the imprisoned Tarrlok in the SeasonFinale, he's [[TheAtoner genuinely regretful about what he did]], and in the end he [[MurderSuicide kills both]] [[RedemptionEqualsDeath himself and Amon]].]]
*** The previous episode also featured a FaceHeelTurn for Hiroshi Sato, Asami's father, who joined up with the Equalists because [[LoveMakesYouEvil a firebender killed his wife]].
* Albedo from the ''WesternAnimation/{{Ben 10}}'' franchise did this. In a flashback from when Ben was 11, he was allied with Ben and Azmuth, and was at least a respectful, decent guy at the time. From ''WesternAnimation/Ben10AlienForce'' onward however, he is a major enemy of Ben Tennyson, for he did turn evil during the TimeSkip between shows.
* ''WesternAnimation/CodenameKidsNextDoor'' had an agent, Numbuh 274, who had appeared in a couple Season 1 and Season 2 episodes become a villain from Season 3 onward after turning 13. However, it turned out that [[spoiler:he'd been working for [[ReverseMole the good side all along]]]] in the penultimate episode of the show.
** The fourth-grade class president also began as a heroic character but, after the KND works to ensure his safe election, it's revealed that he's [[NiceJobBreakingItHero actually their enemy]]. The exact nature of his FaceHeelTurn is something of a mystery: while his blank eyes, CreepyMonotone and Father's EvilLaughter during his FaceHeelTurn implies that he'd been brainwashed, later episodes establish him as not only a [[NotBrainwashed perfectly willing]] heel, but one whose agenda has little connection to Father.
* Raimundo in the season one finale of ''WesternAnimation/XiaolinShowdown''. Shortly into season two, he [[HeelFaceTurn reverses it]] and returns to his friends, but not without suffering some consequences and trust issues.
** Omi undergoes an involuntary turn after coming back from the yin/yang dimension, leaving his good side behind.
* Elyon Brown in ''WesternAnimation/{{WITCH}}''.
* Dinobot in the ''Franchise/{{Transformers}}: WesternAnimation/BeastWars'' episode "Maximal No More." He does a HeelFaceTurn back at the end, though, upon realizing that just because everything's going according to Megatron's plans doesn't mean that Megatron isn't a dangerous madman.
** Blackarachnia in ''WesternAnimation/TransformersAnimated'' pulls her FaceHeelTurn during the (mainly) flashback episode "Along Came A Spider". We discover that when they were in the Autobot Academy, Elita-1, Sentinel, and Optimus went to an organic planet, even though it was forbidden, and they encountered giant spiders. Escaping from the spiders, Elita used her download power to borrow Optimus's grapplers, but ran out of time, falling into a pit full of the spiders when Optimus failed to catch her with his other grappler. She attempted to use her download power on the spiders, but, the spiders being organic, it turned her into a mutated part-organic, part-mechanical Transformer with one of the spiders as her alt-mode. The new signal type made her impossible for Optimus to pick up on his radar, and led him and Sentinel to believe Elita was dead, and Blackarachnia to believe they abandoned her, and she joined the Decepticons.
** Why hasn't anyone mentioned Wheeljack from ''Anime/TransformersArmada''? He has one after believing that Hot Shot abandoned him and turns Decepticon.
** Back to ''Beast Wars'', there is also Rhinox/Tankor in the sequel show ''WesternAnimation/BeastMachines''.
* Tai Lung of ''WesternAnimation/KungFuPanda''.
* A {{Flashback}} episode of ''[[WesternAnimation/ChallengeOfTheGoBots GoBots]]'' revealed that Cy-Kill was once Leader-1's best friend, but frustration over the leadership of Gobotron caused Xy-Kill to join the rebellion (and eventually lead it). In fact, the name of the episode where this is told is "[[Theatre/JuliusCaesar Et Tu, Cy-Kill?]]"
* In ''WesternAnimation/KimPossible'', [[TheDragon Shego]] used to be a superhero before becoming a villain. Various other characters have short heel turns, often for a single episode, including Ron at least twice.
** Most due to the Attitudinator, a HeelFaceTurn[=/=]Face Heel Turn [[AppliedPhlebotinum in a helmet]]. One episode with it caused a HeelFaceRevolvingDoor for everyone but Kim Possible.
* Professor Hamilton, a longtime Superman supporter, as seen in ''WesternAnimation/SupermanTheAnimatedSeries'', turns against him in ''[[WesternAnimation/JusticeLeague Justice League Unlimited]]''.
* In ''WesternAnimation/IronManArmoredAdventures'', Gene Khan does this in spectacular fashion during the second half of the season finale. Given that the writers had spent the entire first season making this character friends with the hero, humanizing him and integrating him into the TrueCompanions, this is actually fairly stunning, especially given that this show loves sympathetic villains being redeemed the way it does.
** One could argue that Gene made his original turn at the start of the series, when he threw down his stepfather and took the role of Mandarin for himself. Outing himself to his friends after they out themselves as Team Iron Man just sealed the deal.
** Whitney Stane has often straddled the line between good and evil ever since she's donned the identity of "Madame Masque", going from UnluckyChildhoodFriend towards Tony to StalkerWithACrush to him, with murderous tendencies towards her father, to redemption, to a brief AntiHero stint as Madame Masque, and LaserGuidedAmnesia that led her to be DemotedToExtra. [[spoiler:Her heel turn is permanently established in "Iron Monger Lives!", where she remembers Tony's identity as Iron Man and her time as Madame Masque. She returns as Masque to hatch an elaborate scheme in order to ruin Tony's life and kill his friends and family. By the time the episode ends, she seems to be continuing her villainous persona and her vendetta.]]
* Jojo does this in a rather epic fashion in ''WesternAnimation/ThePowerpuffGirls'' movie, in what also counts as a CrowningMomentOfAwesome: "[[LargeHam The hobo formerly known as Jojo is no more! From this day on, I shall be known as... MOJO Jojo!]]" Then again, he was EvilAllAlong, so this might not count.
* Gibbs from Creator/AdultSwim's ''WesternAnimation/TitanMaximum''. His heel face turn in the first episode generates the conflict for the rest of the series. Unfortunately, it seems that he's perhaps the only character with any shred of competence.
* A fictional pro wrestling example. In one episode of ''WesternAnimation/{{Futurama}}'', Bender becomes a popular robot wrestler named Bender the Offender. After his popularity fades, management turns him into the Gender Bender.
* Creator/HannaBarbera's Muttley CaptainErsatz as well as Series/{{Columbo}} {{Expy}} Mumbly was made a bad guy in ''WesternAnimation/LaffALympics'' and ''Yogi Bear and the Magical Flight of the Spruce Goose'' because they didn't have all the rights to ''WesternAnimation/WackyRaces'' at the time and [[TheyJustDidntCare couldn't be bothered]] to create a new character.
* In the second ''[[WesternAnimation/TeenageMutantNinjaTurtles2003 TMNT]]'' series, the real Oroku Saki was originally one of a group of warriors that defeated a powerful demon. However Saki [[WithGreatPowerComesGreatInsanity absorbed the power]] and became the Tengu Shredder.
** Vernon Fenwick in the first ''[[WesternAnimation/TeenageMutantNinjaTurtles1987 TMNT]]'' series, to a lesser degree. He is originally, for the most part, is an ally to the Turtles, however, at the beginning of the eight season (the first of the infamous Red Sky Era), after the Channel 6 building is destroyed by Shredder, Vernon then sides with Burne Thompson in seeing the Turtles as menaces to society, as they weren't able to save the building in time (and Shredder blew it up because he believed they captured Krang).
* Parodied in ''WesternAnimation/EdEddNEddy'' when, after a misunderstanding caused the other kids to beat up Captain Melonhead (Jonny) and Splinter the Wonder Wood (Plank), they became The Gourd and Timber the Dark Shard to get revenge on the cul-de-sac. Too bad the movie was over.
* Barnacle Boy in ''WesternAnimation/SpongebobSquarepants'', however it's only for one episode over the fact he wasn't allowed to have an adult-sized Krabby Patty.
* In the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode ''[[Recap/MyLittlePonyFriendshipIsMagicS4E25TwilightsKingdomPart1 Twilights Kingdom Part 1]]'', Discord is swayed into helping Tirek in exchange for true freedom.
** Before then there was Princess Luna's descent into Nightmare Moon during the backstory.
* ''WesternAnimation/WinxClub'': Riven in season one, Bloom (via MindControl) in season two, and [[spoiler:Aisha]] in season four.
* [[spoiler:Aqualad/Kaldur'ahm]] in season two of ''WesternAnimation/YoungJustice'', after he becomes embittered at his former friends for [[spoiler:letting Tula die during a mission gone wrong]] and his own mentor, [[spoiler:Aquaman, for hiding the truth about his real, supervillain father, Black Manta. Kaldur ends up joining him.]]
** [[spoiler:Turns out he only faked his turn and is deep undercover for the Team.]]
* ''WesternAnimation/StarWarsTheCloneWars'': [[spoiler: Senate Commando Captain Argyus (in Season 1), Clone Sergeant Slick (in Season 1 as well), Pong Krell (in Season 4), Barriss Offee (Started out as a heroine in Season 2, becomes a baddie in Season 5).]]
* The Silver Surver on ''WesternAnimation/TheSuperHeroSquadShow'' was so corrupted by the Infinity Sword, that he turns his back on Galactus and even [[TheStarscream tricks]] Thanos into giving him the complete Infinity Gauntlet. It's rare for a Face Heel Turn to pull a Starscream, but Silver Surfer pulls it off well and becomes the new BigBad till the end of the series.
* General Modula did this prior to the start of ''WesternAnimation/SymBionicTitan''. He's seen as one of the good guys in the WholeEpisodeFlashback "Shadows of Youth". What made him turn [[CutShort was not answered]].
* ''WesternAnimation/GreenLanternTheAnimatedSeries'': This happens to Aya after she shuts down her emotions and takes over the Anti-Monitor's body, becoming a KnightTemplar bent on eliminating all organic life to the point that she goes back in time to rewrite the creation of the universe. [[spoiler:She comes to her senses when she accidentally nearly kills Razer.]]
* The DisneyAnimatedCanon
** In ''Disney/TheAristocats'', we get to see Edgar turn into a villain the minute he realizes he can get all of his madam's wealth if he gets rid of her cats.
** Perhaps one of the more tragic examples is Copper from ''Disney/TheFoxAndTheHound'' turning into a full-on hunting dog, [[AntiVillain while still being a nice person at heart]] and [[WeUsedToBeFriends not wanting to kill his former friend]] Tod the fox. So to say, Copper does not become evil, but he's permanently switched to the side of his spiteful old hunting master, which puts him opposite of Tod, left to fulfill the traditional protagonist role.
** Denahi in ''Disney/BrotherBear'', after he thinks a bear killed his brother Kenai (in reality, his brother Kenai was ''[[KarmicTransformation turned]]'' [[BalefulPolymorph into a bear]]). He spends most of the film on a RoaringRampageOfRevenge trying to kill Bear!Kenai until the very end where Kenai is transformed back right before his eyes.
* Lightning near the end of ''WesternAnimation/TotalDrama Revenge of the Island'' after accidentally giving Cameron the win in "Eat Puke and Be Wary", upon which he not only TookALevelInJerkAss, but also he replaces Scott as the BigBad.
** [[spoiler: Dave in the ''Pahkitew Island'' finale, after finding out that Sky is already in a relationship, upon which his SanitySlippage gets even worse.]]
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