* In ''FanFic/BringMeAllYourElderly'', [[spoiler:Creator/MNightShyamalan]] does not take the news that no one wants to see ''The Last Airbender 2'' very well, and after channeling [[EvilOverlord Ozai]] he tries to kill [[TheChosenOne Awng]] for not being right for his movie.

* ''FanFic/SinfulBehaviors'' has Mr. Cosmo. Throughout most of the story, he is calm and collected, rarely raising his voice. By the end, when everything is falling apart, he snaps and attacks Rudy blindly in a desperate attempt to kill him. This results in his untimely death.
* ''FanFic/PlayTheGame'', the sequel, has a more terrifying example with Bardot. Like Mr. Cosmo, he manages to keep his cool, but his tempers flare up a bit more frequently. And when Snap manages to exceed his expectations in a way he did not enjoy, Bardot becomes feral and proceeds to tear apart an already mortally wounded Snap.

* Scythe in ''[[{{Fanfic/AceCombatTheEquestrianWar}} Ace Combat: The Equestrian War]]''. Due to [[spoiler: Garuda team performing a BigDamnHeroes moment and preventing the bombing of Stalliongrad's Eastern Sector]]. When he tries to do it himself later, [[spoiler: Mobius defeats him]].
** [[spoiler: Gilda]] grows gradually more ballistic as Rainbow Dash gains advantage over her during the final duel.
* [[ComicBook/ArchieComicsSonicTheHedgehog Mecha Sally]] in ''{{FanFic/Apprentice}}'' is really emotionless when it comes to taking Eggman's orders. That is until [[{{Manga/Naruto}} Sasuke Uchiha]] comes by and started beating her up, showing he's better than her. With that much insults coming out of him, Sally sure is started to have a breakdown.
* ''FanFic/BurningBlack'' has Remy Buxaplenty suffering from the [[SanitySlippage gradually progressing]] type. It's very alarming to his fairy, Juandissimo, and just as alarming to Timmy. It seems to get worse with every new fact he learns about Timothy and every Dark Spire that gets destroyed.
* ''Fanfic/ChildOfTheStorm'' has Lucius Malfoy, BigBad of Book I, simply slip into a VillainousBSOD, but General Lukin, ArcVillain of ''Forever Red'' in Book II, slips first into a scenery chewing breakdown, mainly aimed at [[spoiler: Maddie]], whose unexpected interference and development from LivingWeapon into a person who can think for herself, then tearing apart his counter-measures, is one of a number of factors causing him to descend into frothing insanity, only made worse by her deflecting his HannibalLecture with a brief ShutUpHannibal. [[spoiler: Dark Phoenix Harry]] tearing apart his plans and obliterating his ace in the hole like it isn't even there sends him into gibbering denial.
** Dracula, the ArcVillain of Book II's ''Bloody Hell'' arc, goes from calm and controlled, as he had been in all his appearances, to a mixture of mindless terror and blind rage when it looks like [[spoiler: the Phoenix is paying him a visit]]. Harry's actually [[spoiler: pretending to be the Phoenix]], and once Dracula realizes that he's been tricked, and that his plan has been comprehensively derailed, he goes absolutely apeshit.
* [[Literature/SherlockHolmes Professor Moriarty]] in ''Fanfic/ChildrenOfTime'' is a FauxAffablyEvil gentleman, smooth-talking and logical, the kind of man who will [[BreakThemByTalking rip your heart to shreds just by talking to you]]. Until the world starts to crumble around him. Then he ''will'' be furious, and he ''will'' make you [[ColdBloodedTorture his new plaything to torture]].
* The version of [[AlphaBitch Lisa]] in ''The Flynns Move To Springfield'' gets a big one at the end, cementing her story-long SanitySlippage. Lisa's attempts to sabotage Isabella's moment in the limelight actually ''helps'' her. At the end, frazzled, humiliated and stark raving mad, she walks up to Isabella backstage and, not realizing everything that she says is being recorded, accidentally outs herself as the cause of all the accidents that occurred.
** She gets an earlier one where she is screaming revenge on Isabella (who is the centre character here, despite the title), while strangling and hitting Maggie. Before then she was an AffablyEvil VillainWithGoodPublicity, after that scene, she becomes more pshycopathic as she gradually loses her sanity.
* In the ''LightNovel/TheFamiliarOfZero''/''VisualNovel/FateStayNight'' crossover ''[[http://www.fanfiction.net/s/6154638/1/The_Hill_of_Swords The Hill Of Swords]]'' the villainess Sheffield starts out as a SmugSuper supremely confident mage that swiftly devolves into a raving lunatic as Shirou outmatches her in each of their encounters. During their final encounter in chapter 22 she spends quite a bit of it just shrieking "DIE!" as Shirou refuses to do just that. The breakdown is so bad that she [[spoiler:falls for one of the oldest tricks in the book: the old "your shoelace is untied" gag.]]
* The BigBad in ''FanFic/TheManWithNoName'' has a mental battle with [[Series/DoctorWho the Doctor]]. [[spoiler: After the villain wins, the Doctor reveals that's [[HoistByHisOwnPetard exactly what he wanted him to do, as his mind is now trapped]]. Breakdown ensues]].
* Loki, the BigBad of ''FanFic/MyLittleAvengers'' (a FusionFic of ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' and Creator/MarvelComics) loses it during the FinalBattle when [[spoiler: Big Macintosh not only regains Thor's powers, but reveals that he isn't Loki's WorthyOpponent brother reborn -- as everyone had assumed -- but just a "mere" earth pony with his powers and some of his memories]]. Likewise, his [[QuirkyMinibossSquad Dark Avengers]] each have small scale ones of their own during their own fights with the other Avengers -- Ghost Flyer has the "ThisCannotBe"-panic variety when Captain Equestria breaks through his [[MindRape Penance Stare]] through ''[[HeroicWillpower sheer willpower]]'', while Iron Monger and Red Skull both go into blind rages when Firebird and Iron Pony turn their own {{Breaking Speech}}es [[ShutUpHannibal back on them]].
* ''FanFic/TheStarsWillAidTheirEscape'': [[BigBad Herald]] actually gets ''[[NotSoStoic angry]]'' when the Princesses, in their true forms, begin to win against him, damaging him faster than he can heal, symbolized by his mask being cracked when he returns to the mortal plain. [[spoiler: While he maintains his composure, he loses enough of his smarts to leave himself wide open to the Elements of Harmony.]]
-->'''Herald''': Your Majesties... you are beginning to frustrate me...
* ''FanFic/TimeLordsAndTerror'': [[WickedWitch Hydia]] has a minor one when Draggle confronts her about how summoning [[EldritchAbomination the SMüz]] is a blindingly stupid idea.
** [[spoiler: The SMüz pretty much ''freaks'' when the ponies start stealing its PKE, killing it.]]
** In the sequel ''FanFic/MinesOfDragonMountain'', [[spoiler: [[BigBad Tirac]]]] ends up frantically begging Gabbro not to stop him by jumping into a lava pit and dragging him in. [[spoiler: And then Gabbro does it [[HeroicSacrifice anyway]].]]
* Happens to [[spoiler:Ludlow]] in ''FanFic/RiseOfTheGaleforces'' [[spoiler:after Violet forces him through an epic HumiliationConga. After all of his contingency plans fail, he shoots her in the back, and when she is revived, he sings "Rock of Ages" and starts hallucinating about going to heaven. Too disgusted with the guy to want anything to do with him at this point, Violet sics the baby tyrannosaurs on him, and the last thing he hears is his own terrified screaming as [[FedToTheBeast he is ripped to shreds and devoured alive.]]]]
* ''Fanfic/{{Equestrylvania}}'': [[CreepyMortician Dirt Nap]] tries to play the TragicVillain card, saying that [[ThenLetMeBeEvil his mistreatment by Ponyville is what led to him joining Dracula]], but Twilight Sparkle [[TheReasonYouSuckSpeech shoots him down]], saying that never having friends doesn't excuse ''[[DealWithTheDevil selling his soul to a demon]]'' and [[spoiler: burning down Ponyville]]. ''Especially'' because nobody ever wanted to be his friend because he was a bitter, antisocial JerkAss, not because he was the somewhat-ugly-looking town undertaker, which he's always used as his excuse for not being liked. This causes him to go berserk.
** When [[WickedWitch Actrise]] realizes that Twilight's OutGambitted her by [[spoiler: channeling a spell through Dracula's rib to the other body parts to hide them]], she starts [[SayMyName screaming Twilight's name]] while beating [[HairRaisingHare the Chronomage]] (who was unfortunate enough to be standing next to her) bloody with her staff. She calms down after a few minutes, but is now determined to see Twilight dead at her hands.
* ''FanFic/AShadowOfTheTitans'': When Raven beats Jade out of his pendant, and during Jade's TheReasonYouSuckSpeech to him, the [[FillerVillain Master of Games]] loses his composure briefly for the only time in the chapter (save his defeat), though he manages to catch himself quickly.
* In the ''WesternAmination/JackieChanAdventures'' and ''WesternAnimation/{{WITCH}}'' crossover fanfic ''Fanfic/{{Kage}}'' (part of ''FanFic/ProjectDarkJade'', like ''Fanfic/AShadowOfTheTitans'' above and ''Fanfic/QueenOfAllOni'' below,), Drago is apparently in the middle of one as he cast the spell that banishes Jade, [[LaughingMad Laughing Madly]] as he does so, and continuing to do so even as he and his father are dragged out of the earthly reality.
* ''FanFic/JusticeLeagueOfEquestria'':
** ''Mare of Steel'':
*** Trixie has one early on when Rainbow Dash says she's "not worth it" (that is, not worth fighting her over who's superior).
*** [[DiscOneFinalBoss General Zod]] has one during his final fight with Supermare as she starts to overpower him, finally deciding to [[spoiler: [[TakingYouWithMe blow both of them, and Canterlot, to kingdom come]].]]
*** [[GeneralRipper Steel Wing]] loses it after Luna arrests him for harassing Supermare, constantly ranting about the Princesses being in a conspiracy with Supermare to take over Equestria.
*** ComicBook/{{Brainiac}}'s is much less noticeable, but after Supermare manages to defeat his supposedly foolproof SadisticChoice, he actually gets ''[[NotSoStoic angry]]'' and decides that instead of adding her to his collection, he'll just kill her.
--->"Kara Jor-El... You have become an annoyance."
** ''The Princess of Themyscira'': [[BigBad Ares]] completely loses it during the FinalBattle when Diana manages to destroy the [[ArtifactOfDoom Alicorn Amulet]] and close the portal he's opened to Tartarus. He's left desperately trying to keep the portal open [[spoiler: and when he starts getting sucked in, lashes out and grabs Diana in an attempt to [[TakingYouWithMe drag her down with him]]]].
* The MagicalGirl CrossOver ''FanFic/ShatteredSkies'' begins with one, specifically that of [[Anime/SmilePrettyCure Joker]]. During the final battle of the series, he loses his faith in his master and creator, [[BigBad Emperor Pierrot]], and realizes his purpose was for nothing... Then he wakes up in the afterlife, meets the UltimateEvil, and resolves to go OmnicidalManiac on ''everything'' to get revenge.
* ''Fanfic/TheBridge'':
** When King Sombra is confronted by Princess Cadance, he briefly mistakes her for Princess Amore Diamante, then starts screaming and ranting that it isn't possible because he had personally killed her a thousand years ago. He calms down a bit when Cadance corrects him, but then savagely attacks her while ranting about how much he hated Amore. He has another one when Cadance manages to break his nose during their fight.
** [[spoiler: [[BigBad Bagan]]]] throws a tantrum and thrashes the room while thinking about how Mothra and Godzilla interfered with his invasion of Canterlot. However, after about a minute, he calms down and says it was but a minor setback.
** [[spoiler:Grand King Ghidorah]] loses it when he is mortally wounded through the combined efforts of Godzilla Junior and Xenilla. Faced with the notion of dying without accomplishing his lifelong goal [[spoiler:of creating or becoming something powerful enough to defeat Bagan]], he snaps and powers up his BreathWeapon to perform a TakingYouWithMe on ''all of Equestria''. His state of mind only gets worse as he starts losing the BeamOWar. [[spoiler:He calms down again when he sees a vision of a being who will be able to defeat Bagan and calmly accepts his death as the Godzillas' power destroys him.]]
* ''Fanfic/{{Worldfall}}'': [[spoiler: During [[FinalBattle Operation Endgame]], [[TheStarscream Straha]] completely loses his shit as he realizes that the "primitive" humans are about to wipe out the combined forces of what's left of the Conquest Fleet and the Thuktun Flishithy. The Herdmaster uses this as an opening to kill him.]]
* The Review Team series has a [[VillainousBreakdown/TheReviewTeam subpage dedicated to this trope.]] Turns out, the villains there don't have the most graceful of falls.
* ''FanFic/SoulChess'': Aizen ''loses it'' after Lelouch refuses to acknowledge him at the end of their second confrontation. Viewing him as [[WorthyOpponent his rival]], the one person that is (intellectually) on his level, the fact that Lelouch won't even renounce his ideals is the ultimate insult to Aizen's pride. After that, it becomes clear that while Aizen's main goal is still usurping the Soul King, screwing over Lelouch is a very, ''very'' close second.

* In ''FanFic/AndAgain'', the Mastermind behind the DeadlyGame of ''VisualNovel/DanganRonpa'' throws a hissy fit when their [[TheMole mole]] murders one of the others, then promptly confesses to the crime, denying them the pleasure of a drawn out, dramatic trial and execution. By the end of that loop, they completely break down when Naegi [[spoiler:reveals her staged murder as a hoax, meaning her game ended with only one murder, no real trials, and none of the drama and despair she'd been hoping for]].
* ''Fanfic/ThreePointShot'' diverges from ''VisualNovel/NewDanganRonpaV3'' when, during the investigation of the first murder, Kokichi throws the shot put ball that was the murder weapon up onto the bookshelf, thus inspiring Shuichi to investigate further, thus eventually revealing that Kaede [[spoiler:didn't kill Rantaro- the mastermind did]]. At the end of the class trial, [[spoiler:after being convicted of murder]], the mastermind is ''furious'' with Kaede for not playing the role intended for her, and even more so with Kokichi for having "ruined everything with one [[PrecisionFStrike fucking]] joke!"

* In ''FanFic/FeverDreams'' when [[spoiler: L screws up his plan [[SlashFic to get them back together]]]] Light very calmly goes up to his room, collapses into bed, and screams into his pillow.
-->'''Rem''': Light Yagami, I did not realize you were capable of having feelings.

* Freeza gets it bad in ''WebVideo/DragonBallAbridged'' during his fight with Goku, due to his exposure to Goku's [[IdiotHero remarkable stupidity.]]

* [[spoiler: Vaticus]] in FanFic/TheTaintedGrimoire had a brief one ''before'' being defeated. He became a GracefulLoser after being defeated.

* ''FanFic/InThisWorldAndTheNext'' has [[RonTheDeathEater Dumbledore]] literally go insane after [[spoiler:Harry defeats Voldemort before Dumbledore can groom him to sacrifice himself]].
* In ''FanFic/TheJadedEyesSeries'' Harry/Tristan has one at the Yule Ball after having a rather violent run-in with his birth family. Tristan [[TakingTheBullet took a cutting curse]] that Lily fired at his adopted mother and his shirt was destroyed in the process, putting his scars, and the CarvedMark [[MarkOfShame of "FREAK" on display]] for everyone to see and as an added bonus Lily [[SecretIdentity finally recognized that Tristan Winter is her missing son Harry Potter]]. Tristan's reaction is to go LaughingMad while [[BloodIsTheNewBlack covered in his own blood]]. He wasn't particularly mentally stable at the moment anyway considering he had just finished [[spoiler: committing mass genocide]] and the accumulated shame, guilt, and humiliation proved to be just too much of a strain on what was left of his sanity.
* In ''FanFic/TheVerySecretDiary'', Tom has small amounts of these, usually when Ginny is able to outsmart Tom. He responds with violent, murderous threats, or with [[TranquilFury dead silence]], or a mix of both.

* ''FanFic/QueenOfAllOni'': [[SmugSnake Lung]] starts cracking when it becomes evident that his plan to break Jade to his will is failing, and then he breaks completely when her minions show up to save her.
** Drago eventually has one due to the repeated failures of his attempts to gain power in the past. He ultimately snaps and rants that rather than doing things strategically, he's just going to smash everyone and everything in sight and see what effect that has on the timeline. [[spoiler: Fortunately, he's banished back to the future before he has a chance to.]]
** Jade herself has one when her [[SanitySlippage PTSD]] from Lung's actions finally hits a breaking point. After Tohru's failed attempt to capture her in the Vault of Endless Night, she snaps, becoming paranoid and delusional, convinced that the heroes (and humans in general) are out to either [[SealedEvilInACan seal]] or kill her (and her emotional [[CallingTheOldManOut confrontation]] with her father doesn't help, least of all the reveal that she was accidentally conceived and nearly aborted).
* ''FanFic/{{Webwork}}'':
** Daolon Wong completely loses his shit when Uncle, who's gained the upper hand in their WizardDuel, says that [[DontYouDarePityMe he pities him]].
** [[spoiler: After being beaten and BroughtDownToNormal, Valmont [[LaughingMad breaks down and laughs]] as he's arrested, believing that his life is a joke only he gets, telling Jackie that ''he'' won in the end because there was nowhere they could put him that was ''worse'' than the crummy apartment that he was in before, and at least in jail he'll have three meals a day, and sarcastically wishes them good luck in their constant, thankless and futile quest against the supernatural.]]

* In the ''[[FanFic/AllThingsProbableSeries All Things Probable]]'' story, ''[[http://www.fanfiction.net/s/3785522/34/A_Friend_In_Darkness A Friend In Darkness]]'', Monkey Fist, who was usually the most calm-minded and suave villain in the cartoon, suffers from one of these in the final battle of the story after being humiliated, reducing him to raging and shrieking like an actual monkey while unleashing the dark power he had been cursed by. The irony is, his breakdown wasn't caused by Ron Stoppable, his actual ArchEnemy and the one more likely to drive him into one.

* In [[http://www.fanfiction.net/s/4927091/1/Girls_School Girls' School]], Lucy Horowitz, a girl accused of holding down another girl as the other girl was raped, has one after learning that [[spoiler: the rapist was caught, thus denying her a bargaining chip for a reduced sentence]].

* In the continuation fanfic [[FanFic/BookFiveLegends Book Five: Legends]] we have [[spoiler:Temuji]]. Normally calm and clinical, like a [[spoiler:good medic]] should be, they start to break down in the final chapters of the story when [[spoiler:he cannot seem to save his mother and is having trouble controlling his new powers]]. In the end, they're a raging, rampaging monster, [[spoiler:crying out for his mommy as he tries to destroy Korra, irrationally blaming her for everything]]. In addition, [[spoiler:Fumiko]] has a similar breakdown when the most important thing to them, [[spoiler:her BigBro Temuji]] is dead. To say they do not take it well is a massive [[{{Understatement}} understatement]]. It completely shatters their [[spoiler:fun loving personality, leaving them a crying mess]].

* In ''[[http://www.fanfiction.net/s/6321817/1/The_Legend_of_Spyro_Retelling_A_New_Beginning A Dark Beginning]]'', Dredd, the commanding Ape on the Tall Plains, has one of these after he discovers Kane escaped, going from FauxAffablyEvil to screaming his death threats and his YouHaveFailedMe trait surfacing. After [[spoiler:he falls for Spyro and company's plan to free and arm his captives, resulting in his entire group to be wiped out, he's left stunned at what happened before getting enraged and going into a LastVillainStand against Kane that leads to his demise.]]

* ''FanFic/SaetwosStory'': During the FinalBattle, [[BigBad Romelau]] completely loses his shit when the Zoombinis manage to turn the tide against the Fleens. He just berserkly focuses on taking down [[TheHero Saetwo]], regardless of everything else. [[spoiler: This ends up contributing to his DisneyVillainDeath.]]

* In ''Fanfic/ProjectGethinator'', the BigBad, Admiral Daro'Xen, who is {{Yandere}} in a big way for Commander Shepard, loses it quite spectacularly after Shepard decisively turns down her advances and calls her on her crazy scheme and her obsession with him. [[spoiler:Her breakdown is of literally star-system-shattering proportions -- she takes the same mineral scanner that Prazza, Tali's idiot crewman from ''Fanfic/IngloriousBoshtets'', accidentally used to make a star go supernova and uses it on the main star of the Eta Carinae system to make the thing go ''hyper-nova'', making sure to have the ''Normandy's'' drive core disabled so Shepard, Tali and the crew cannot escape. When the crew does manage to escape JustInTime (via Shepard's quick thinking and Legion's advanced skills getting everyone out of there alive), Xen proceeds to lose it ''even further'']].

* In ''FanFic/MegaManDefenderOfTheHumanRace'', ever since episode 4 and the Gamma ordeal, Wily's been slowly losing it.
** Mr. Black's been losing it as well, especially given his replacement, Tiesel Bonne.

* ''FanFic/ABriefHistoryOfEquestria'' has Sullamander (the pegasi Supreme Commander before [[Recap/MyLittlePonyFriendshipIsMagicS2E13HearthsWarmingEve Hurricane]]), who wasn't [[TheCaligula quite sane to begin with]], completely fall into anger, paranoia, and madness during her last days as Hurricane and his lover General Wind Whistler led a successful coup against her. Her last confirmed action (everything else being unconfirmed myth and rumor) before her final duel with Hurricane was to accuse her loyal generals of being traitors and killing them, before fighting Hurricane to the death; during the fight, it seems she didn't even ''notice'' her large assortment of wounds, being so solely focused on killing her rival.
** Viscount Arsenic ended up falling apart during the [[MeleeATrois Lake Trot Crisis]], due to his supposedly superior troops being curbstomped by the Hyracotherium Republic forces under Lady Cripps (the fact that she was a [[PoliticallyIncorrectVillain mare]] contributed to it). This eventually led to him trying to personally lead his forces in the final naval battle of the conflict, which got him killed.
* ''Fanfic/EarthAndSky'': [[DiscOneFinalBoss Diamond Tiara]] breaks down completely in light of all her plans falling apart, [[spoiler: being captured by the changelings, and then being left to die in the badlands by them because [[EvenEvilHasStandards even they can't stand her]]]]. By the end, she's so broken that the only thing keeping her going is her [[ThePowerOfHate hatred for Apple Bloom]] and her determination not to see her rival beat her. [[spoiler: She starts to get better when her life is saved.]]
** Professor Destiny completely loses what sanity he had left after he and his brother [[spoiler: are disqualified from the race]]. He becomes determined to finish the race no matter what, and basically turns their flight harness into a weapon and the race into a suicide run, not even caring when they're about to hit the shield covering Canterlot. [[spoiler: They survive, and it seems he finally had some sense knocked into him.]]
* [[FanFic/EquestriaAHistoryRevealed Equestria: A History Revealed]]: In the Civil War flashback, after learning of her loss at the Battle of Canterlot, Princess Luna began to do this as she slowly went insane. It got even worse when she realized the war was lost upon the final battle at the Everfree fields, and she started thinking of all the crimes she committed in the war. This would all serve to help [[ThenLetMeBeEvil her eventual complete transformation into Nightmare Moon]], despite the deep regret she had for her actions towards the end.
* ''FanFic/GettingBackOnYourHooves'': [[BigBad Checker Monarch]], whose special talent is [[ManipulativeBastard manipulating other ponies]] and has been doing so all story in order to ruin [[spoiler: [[CainAndAbel her sister]]]] Trixie's life, [[FreakOut Freaks Out]] whenever her plans fail. However, she really [[SanitySlippage starts cracking]] when her plan to ruin Trixie's charity show is prevented at every end by her friends (who are aware that ''someone'' is trying to ruin Trixie), and finally develops full-blown [[FanNickname Cutie Mark Failure Insanity Syndrome]] when [[spoiler: she tries to MindRape Trixie with a dream infiltration spell, only for Trixie to see through the mind games, fight back, and defeat her]], something she simply [[ThisCannotBe cannot comprehend]].
** Then, what little sanity she has left goes out the window when [[spoiler: Helping Hoof and the Diamond Dogs turn on her and help Trixie and the Mane Six set up an EngineeredPublicConfession]]. This breakdown continues through the FinalBattle and is ultimately so severe that [[spoiler:she's left completely insane and will likely spend the rest of her life in an insane asylum.]]
* ''[[FanFic/HeiroftheNightmare Heir of the Nightmare]]'': Nightmare Moon suffers a particularly terrifying one [[spoiler: after her [[CallingTheOldManOut daughter Twilight tells her off for her insanity]] ]]. Nightmare first unleashes a destructive wave that wrecks Canterlot Castle. [[spoiler: Then, while chasing after Twilight, she speaks in a crazed tone, while claiming their chase to be like hide and seek]].
* ''FanFic/TheImmortalGame'' has a couple. First, [[SuperpoweredEvilSide Nihilus]] -- who wasn't [[AxCrazy all that sane to begin with]] -- completely loses her shit when [[spoiler: Rainbow Dash not only breaks free of her mind control, but she learns that she ''hasn't'' corrupted the Elements of Harmony, as she thought]]. Then, near the end of the story, [[RoyalBrat Empyrean]] totally falls apart when the Mane Six [[StormingTheCastle break into his throne room]] to confront him, and fires off the magical equivalent of a WaveMotionGun to try and fry them [[spoiler: only for the Elements to be used to strip his powers instead]].
** [[spoiler: [[BigBad Titan]] completely falls apart when Twilight performs a BreakingLecture on him during their [[FinalBattle finale duel]], which gives her the chance to strip him of his powers. After this, he continues to try to fight her anyway, [[SuicideByCop knowing perfectly well that it'll get him killed]].]]
* ''FanFic/InnerDemons'': Twilight Sparkle [[AxCrazy stopped being sane]] the moment she was consumed by her [[EnemyWithin Queen persona]], but even by that standard she ''really'' flips her shit during the Battle of Fillydelphia when she realizes that her [[VillainousIncest beloved brother]] is choosing to stand against her with the protagonists. She starts ranting and screaming that she'll kill all the heroes, Shining Armor included, and is only stopped from carrying out an execution on Cadence by the other heroes arriving in time. Interestingly, they also somewhat accidentally calm her down from the breakdown when they then confront her over [[spoiler: [[TheDragon Trixie]] ([[OnlyMostlyDead nearly]]) killing Rarity on her orders.]]
** She has a ''much'' more severe breakdown when [[spoiler: Trixie -- the only pony left she felt she could trust and call a friend -- dies right in front of her]]. She starts laughing and crying, before the emotional trauma causes her to [[OneWingedAngel transform into an Alicorn]]. She then declares that [[spoiler: she's going to unleash the [[LegionsOfHell hordes of Tartarus]], because if she can't be Equestria's [[EvilOverlord ruler]], she'll be its [[OmnicidalManiac destroyer]].]]
*** On the plus side, the shock of all this disrupts all her spells, thus [[spoiler: restoring Cadence's powers, freeing Luna and the Royal Guard from her MindControl, and freeing Celestia from her [[TakenForGranite stone imprisonment]]]].
* ''FanFic/MyLittleMagesTheNightmaresReturn'': [[BigBad Nightmare Moon]], after spending the whole story in a self-assured confidence that the heroes can't even hurt her let alone stop her, panics when they manage to active the Elements of Harmony, and flies into a blind rage when they actually manage to hurt her. As is pointed out in the story, she even stops using the RoyalWe she'd been using all story.
* FanFic/TheNuptialverse: At the climax of ''Families'', [[BigBad Olive Branch]] completely falls apart when [[spoiler: Celestia laughs in his face, pointing out how incredibly [[AndThenWhat flawed]] his master plan is, and he realizes she's right]]. By the end, the formerly [[SmugSnake smug]] manipulator is wildly crying and begging the Princesses not to hurt him as he's dragged off and arrested.
* [[spoiler:[[EnemyWithin Loneliness]]]] from the ''FanFic/PonyPOVSeries'' loses her cool a bit every time Twilight manages to fend off her mind games, but snaps completely once [[spoiler:Twilight actually manages to break through to Trixie. Loneliness goes OneWingedAngel and drops her facade of "love" towards Trixie, breaking her leg and outright trying to ''murder'' Twilight rather than let Trixie escape her clutches.]]
** Discord has two in "[[{{Prequel}} Origins]]". The first is when Mimic reveals to him that the bridge between Ponyland and Earth has been destroyed, thus protecting humanity from him. Discord is rendered ''speechless'' for a few minutes and left so beside himself with anger as to forget he's an omnipotent RealityWarper long enough for Mimic to perform her now famous DyingMomentOfAwesome. The second comes when [[spoiler:Shady, TheDragon and earthly mother whose love for him he's manipulated for 1000 years, betrays him, allowing Celestia and Luna to defeat him.]]
*** During Mind Games, while he's working on [[BreakTheCutie breaking]] Diamond Tiara, she somehow [[spoiler: views his memories of being raised happily by his mortal mother Shady (Diamond's ancestor)]]. This causes Discord to flip out.
** A flashback during the Dark World arc reveals that the [[BadFuture Epilogue]] version of Discord had another one when, in the aftermath of an attempted AlienInvasion of Equestria, he went after the aliens' leader, only for [[spoiler: him to take pity on the [[TabletopGame/{{Warhammer40000}} sick old man]] and return him to perfect health for a day]]. The breakdown occurs as a result of Discord having ''[[EvilCannotComprehendGood no idea]]'' why he did it, even after [[TheDragon Twilight Tragedy]] explains it to him.
*** More recently in Dark World, Discord has another small scale one when [[TheVoice the Nameless Passenger]] gives him a TheReasonYouSuckSpeech, but he gets over it pretty quickly.
** Also in the Dark World, Traitor Dash slowly loses it over the course of the Duel of Tears, as she desperately tries to kill Twilight, all while trying to convince her, the others, and ''herself'' that it's [[WellIntentionedExtremist the right thing to do]]. [[spoiler: Twilight actually invokes this to defeat her, and then uses the memory spell to [[HeelFaceTurn restore her]].]]
** [[GeneralRipper General-Admiral Makarov]], the BigBad of the Shining Armor Arc, has a small one when Sergeant Thunderchild [[SpannerInTheWorks ruins]] his plan to capture and/or kill Shining Armor, though he recovers quick enough to order a retreat of his forces.
*** He suffers a more serious one when [[RebelLeader Dima]] [[spoiler: intentionally [[HeroicSacrifice sacrifices his life]]]] in order to [[DidYouJustFlipOffCthulhu screw with Makarov's "script"]]; this act enrages Makarov so much that he suffers temporary GlamourFailure, and during his next attack is still furious, rather than regaining his calm like before.
** [[TheStarscream The Valeyard]] ends up having one as well when the Dark World Elements of Harmony discover that [[spoiler: he's using a regeneration template to preserve his personality]] and he starts frantically trying to stop them from exploiting this fact to beat him. [[spoiler: He fails.]]
** Again in the Dark World, [[PsychopathicManChild Fluttercruel]] has one when Rarity turns the tables on her by shooting [[{{Golem}} Tom's]] [[TragicKeepsake fragment]] [[EyeScream through her eye]] and subsequently manages to [[spoiler: mortally wound her]]. Fluttercruel basically throws a temper tantrum, screaming how Rarity "cheated" and calling her every profanity she can muster [[spoiler: until Rarity finishes her off]].
*** After [[spoiler: surviving by [[BodySurf possessing Sparkler's body]]]], 'Cruel starts to crack as the heroes start to poke holes in her life philosophy (expressing love through violence and torture), but doesn't have a full emotional breakdown until [[spoiler: Rancor betrays and mortally wounds Discord]]. She's unable to accept this and blames it on the heroes, before she [[spoiler: absorbs the Shadows of Existence and [[OneWingedAngel turns into a full Draconequus]]]], and starts ranting on how she'll kill them and ''[[OmnicidalManiac everything else]]'' until she and her father are all that's left. By the time the heroes defeat her, she's reduced to a ranting, screaming, whimpering mess who was hallucinating for most of the fight.
** During the same fight, [[PhysicalGod Rancor]] has a relatively mild one when [[spoiler: [[GeniusBruiser Spike]] turns the fight around and]] she actually starts feeling ''pain''. She goes from smug AffablyEvil villainous to whining like any teen not getting their way. Justified because she ''is'' a teenager (relatively speaking) and being [[NighInvulnerability immune to violence]] means she hasn't gotten hurt all that much, and thus hasn't experienced pain frequently enough to build up a tolerance to it.
** Shortly after the above two, [[TheBrute Angry Pie]] starts to crack (moreso [[AxCrazy than usual]]) due to her former friends' continued efforts to [[IKnowYoureInThereSomewhereFight get through to her]], in a sort of combo of EvilCannotComprehendGood and LogicBomb (though forcing herself to [[spoiler: use the Element of Magic she stole from Twilight]] probably wasn't helping). And then she just falls apart when [[spoiler: Twilight, who she thought she had killed, is not only revealed to be NotQuiteDead, but then [[JumpingOffTheSlipperySlope jumps off the slippery slope]] by starting to ''torture her to death'' as punishment]].
** [[spoiler:[[TrueFinalBoss The Nameless Passenger/Nightmare Eclipse/Paradox]] has several over the course of Dark World, but always manages to recover. However, as the FinalBattle rages on and the heroes keep countering her attempts and the BigDamnHeroes keep showing up, her composure begins to slip more and more frequently as her frustration and anger mounts. The Benevolent Interloper even mentions she's getting more and more desperate. This reaches its zenith when Minty Pie [[EleventhHourRanger enters the battle]] and refuses to stay down, ultimately thwarting her attempt to corrupt Twilight.]]
---> [[spoiler:'''Nightmare Paradox''']]: [[spoiler:[[WhyWontYouDie YOU! WHAT PART OF LIE ON THE GROUND AND SILENTLY BLEED INTO DEATH WAS HARD TO UNDERSTAND?!]]]]
*** [[spoiler:Her biggest and final one starts with Discord [[BackupFromOtherworld calling her from the afterlife using Anarchy's cellphone]] and telling her Havoc isn't going to ''let'' her overwrite Cruelty's Draconequusification, meaning he ''won'' by finally getting a loop where Fluttercruel ''lives'', and she's not getting her back. This results in Paradox blowing her top and screaming that Mad Tiara and Screwball are going to be her new targets...then [[OhCrap realizing Discord just distracted her from Twilight charging her final spell]]. She continues to fall apart as Twilight's spell [[GondorCallsForAid summons the]] [[CrisisCrossover G1, G2, G3, and G4 (the pre-Discord versions) mane six]] to the present (reigniting the Princesses' Elements), putting her on the receiving end of ''six'' sets of Elements. Finally, her parents restrain her and she receives a BreakingLecture from Rota Fortuna that makes her realize she really ''has'' become NotSoDifferent from Discord. She goes ''catatonic'' from the shock, and by the time we last see her is reduced to little more than a broken shell of herself [[VillainsWantMercy begging Twilight not to]] [[KarmicDeath make her fuse with her]].]]
** Throughout "AJ's Dreams", [[KnightTemplar Nightmare Mirror]] stays calm and speaks in an even, cultured tone. But as Applejack and Orangejack continue to defy her, the more she starts to crack, along with her voice starting to degrade back into [[spoiler: her normal country accent]].
** [[spoiler: The Defense Attorney in the trial for Starlight's soul in her 7 Dreams/Nightmare story has one when Starlight declares herself guilty and is forgiven by the Prosecutor. She goes on a tirade, flipping the table over and screaming Starlight wasn't supposed to be forgiven...[[SubvertedTrope then laughs and says it was fun]]. Turns out "she" was Havoc the entire time (the Father of All Alicorns was the Prosecutor) and He pretended to have a breakdown when he saw he was losing because [[ItAmusedMe It Amused Him]].]]
** [[spoiler:[[Series/DoctorWho The Master]] has one when Minuette resists his attempts to tempt her into opening her fob watch and [[SealedInsideAPersonShapedCan become him again]], eventually losing his cool and screaming at her.]]
--> [[spoiler:'''The Master''']]: YOU EQUINE FOOL! [[spoiler:You are ME! You are the MASTER!]]
** Queen Chrysalis has one when [[spoiler: [[SpannerInTheWorks Blueblood arrives with the real Cadence at the wedding]]]], becoming so enraged she tries to vaporize him, blowing her cover and forcing her to reveal herself. She manages to regain her composure and the advantage, but she spends most of the chapter openly furious.
*** [[spoiler:She has a ''bigger'' one when Applebloom arrives in the throne room and frees Applejack, ruining her thus far flawless plan to defeat the heroes (which was on the verge of allowing her to kill Twilight and brainwash her team according to the Interviewers). She goes ''completely'' berserk and flies into a psychotic rage trying to kill her. After Applejack and Applebloom use AJ's LivingLieDetector powers and the Apple Family's PowerOfLove to shatter her self deception that [[ThatManIsDead her past is dead]], she ''snaps'' and ends her scene laughing with an insane smile, swearing to make Twilight suffer. Even ''her Changelings'' are freaked out.]] Noticeably, she doesn't seem to fully recover from this breakdown and shows signs of SanitySlippage afterwards. [[spoiler:Such as [[HearingVoices responding to Maua]], her ChildhoodFriend who she drained as a filly and openly mentioning things she knows via her PeggySue status.]]
*** Her ''biggest'' comes when [[spoiler:Applejack points out her [[AGodIAm ascension into an Alicorn]] wasn't ''just'' the power boost she expected it to be and [[VillainousBSOD came with a new heart]]. Finding herself unable to enjoy her victory as she actually ''cares'' that she caused untold amounts of misery to get to it, she ''loses it'' and goes berserk.]]
** Professor Kabuto has one when [[spoiler:Garnet and Misfit injects him with a counteragent to his OneWingedAngel form, resulting in not only his defeat but a SuperpowerMeltdown that [[KarmicTransformation turns him into an Earth Pony]]. He's reduced to absolute fury and charges Garnet in a blind rage to try and kill her, resulting in him being knocked out cold.]] He gets ''worse'' afterwards [[spoiler:[[DrivenToSuicide trying to kill himself]] and suffering SanitySlippage due to being given a, in his mind, FateWorseThanDeath.]]
* The ''Fanfic/PonyPOVSeriesChaosVerse'': By the time [[spoiler: [[BigBad Nightmare Phobia]]]] goes OneWingedAngel, she's completely lost what [[AxCrazy little sanity she had left]] and turned into an OmnicidalManiac. When the FinalBattle begins to turn against her, she completely falls apart, going from threats to ''[[VillainsWantMercy begging for her life]]'', trying to convince the heroes to spare her.
* Discord had a ''hysterical'' breakdown in ''FanFic/{{Progress}}'', when Luna [[AndIMustScream turned him to stone in the dream world]]. He went from psychotic fury to frantically pleading for mercy ''in the space of a few seconds.''
* ''FanFic/RealityChecksNyxverse'':
** ''Alicornundrum'': [[SmugSnake Duke Blueblood]] (Prince Blueblood's father) ends up having one at the climax when [[spoiler: not only are he and his co-conspirators exposed and arrested for their treason against the throne, but it's made clear that even if his coup had worked, the Celestial Council would have stepped in and prevented his bid to TakeOverTheWorld]]. His mind basically shuts down at this, reducing him to quivering on the floor, sucking his hoof like a foal. It later turns out that this is because the shock actually caused him to burst several blood vessels in his brain, causing enough damage to reduce his mental state to that of a foal.
** ''Tirek Gets A Righteous Beatdown'': After the titular beatdown, then the rest of the HumiliationConga that it's a part of, Tirek completely falls apart. When he gets back to Tartarus, he actually barricades himself in his cell and curls up in the fetal position.
* ''FanFic/ThePiecesLieWhereTheyFell'': [[spoiler: The Nightmare, when it realizes it just accidentally revealed the key to its defeat to the Bearers, flips out and tries to kill five of them before Xvital can get there. It fails.]]

* ''Fanfic/TheSecondTry'':The fall of [[spoiler:the first [[{{Robeast}} MP-EVA]] during the final battle]] marks the shift of SEELE from the Omniscient Council of Vagueness they were in-show to a Not-So-Omniscient Council of Bickering over the ruin of [[spoiler:their plans for Instrumentality]] and the potential ways to try to salvage them. The unnoticed fatal [[spoiler:Villainous BSOD their chairman suffered while they were arguing]] doesn't help to clear the air.

[[AC: ''Manga/OnePiece'']]
* ''FanFic/ThisBites'':
** Bellamy has one when he hears Luffy's proclamation (amped by Soundbite), that the City of Gold did exist in the sky all along.
** The entirety of the Enies Lobby incident is turning into this for Sengoku, who is increasingly stressed out and enraged by the ongoing actions of the Straw Hats and the other Super Rookies (even suffering a ''heart attack'' over it). By the time [[spoiler:Spandam spills the beans on his plans to overthrow the Five Elder Stars, live on the SBS]], he has a SlasherSmile on his face when he informs Spandam of his eventual fate once he returns to HQ.

[[AC: ''Franchise/{{Pokemon}}'']]
* The Sensational Sisters in ''Fanfic/PokemonResetBloodlines'', in a desperate attempt to keep their Gym, drag Ash into an unfair battle to make sure he loses. They get increasingly angry when they're unable to defeat Ash's Pokémon, despite using their strongest team, culminating in a borderline murderous rage after Ash wins the battle. Even as they're being arrested by Nurse Joy, they give off furious and half-insane screams.

* [[ManOfWealthAndTaste Dufayel]], the BigBad of ''Fanfic/OldWest'', is FauxAffablyEvil for most of the story, but the continuous setbacks in claiming the heroes' lands stretch his patience bit by bit, especially because [[spoiler:he's trying to claim the gold there to avoid bankruptcy]]. Finally in the 28th chapter, he loses it and ruins his [[ClassyCane expensive cane]] by using it to smash objects in his office. When the [[spoiler:bankruptcy]] he's been dreading finally occurs in the 31st chapter, he [[TantrumThrowing throws his chair]] against the wall and [[ThisMeansWar gives his cronies the order to drive the folks away violently if they have to]].

* Several in ''Fanfic/WithStringsAttached'':
** Kerrun as she realizes that the four aren't on her side after all; and, later, when she goes off the deep end completely and declares that every skahs in Ehndris is actually an Idri.
** Jeft has two:
*** [[spoiler: When the Hunter makes friends with the four instead of fighting them, Jeft is so pissed at this subversion of his favorite gaming character that he sics square miles of undead on them as payback. He freaks out completely when the five manage to destroy the Heart of Evil powering the whole show.]]
*** [[spoiler: A few hours later, when the Hunter agrees to ditch his {{BFS}} in order to return to C'hou with the four, the still-simmering Jeft goes crazy with anger and turns the sword back into the demon it always was in an attempt to kill the four and regain control of the Hunter.]]

* ''FanFic/SonicXDarkChaos'' has a number.
** Tsali completely loses his cool when he is defeated by Super Sonic and friends.
** In Episode 74 Tsali has another mental breakdown after discovering Maledict was responsible for the entire Metarex war and everything that had happened to him. In the same Episode, the Metarex leaders (especially Dark Oak) have their own breakdowns when Maledict captures them and reveals that [[TheChessmaster they were his pawns all along]].
** Maledict himself has a minor breakdown from Sonic's (apparent) death in Episode 64. However, when Sonic refuses his WeCanRuleTogether offer, [[spoiler: D'Arnazhee destroys the Galaxy Crusher's firing mechanism]], and [[spoiler: Jesus and the Angels [[BigDamnHeroes come to Sonic's rescue]]]] in Episode 75, he [[ChewingTheScenery utterly loses it]] and [[CurbStompBattle unleashes his true power]].
** The Metarex leaders, especially Dark Oak himself, have a collective breakdown after their decisive defeat in Episode 64.

* In ''[[FanFic/UltimateSpiderWoman Ultimate Spider-Woman: Change With The Light]]'', Spider-Woman's ArchEnemy Jack O' Lantern's sanity has been going downhill for a very long time. Developing an increasingly crazed obsession with his teenage nemesis for her constantly interfering in his [[ForTheEvulz "fun"]], he hatches a plan to mentally break her and make her his heir. When she overcomes that, he goes berserk in an attempt to kill her. When she defeats him and he's hauled off to jail, he's raving insanely in his cell and hallucinating everything from screaming witches, dancing skeletons and flaming pumpkins to giant human-headed spiders that alternately have the face of Spider-Woman or her civilian identity of Mary Jane Watson.

* In the penultimate chapter of ''Fanfic/BreakingPoint,'' [[spoiler: Medusa]] has one when Chrona continually refuses to let [[spoiler: her [[GrandTheftMe take over his body]] ]] despite being tortured. Especially jarring since in the original series, [[spoiler: she]] never once comes ''close'' to losing her cool, hardly even raising her voice.

* In ''FanFic/TouhouIbunshu'', after [[spoiler:Yukari]]'s attempt to destroy Gensokyo has failed, she starts breaking into pieces when Yuyuko confronts her on her manipulations, and devolves into outright savagery when confronted by Ran, [[spoiler:who uses the wording of her shikigami contract to start siphoning Yukari's power in an attempt to kill her]]. However, she ends up completely ''shattered'' when her final pawn, [[spoiler:Chen]], sides with Ran, leaving her completely alone. She gets better, but at the time it's her emotional nadir.
* Lunarian Lord Tenshou of ''[[FanFic/IcedFairysANewWorld A New World]]'', who was a mediocre commander to begin with, always second-guessing himself and doubting his own orders, has one when Yukari reveals her full plan and just how thoroughly he has been owned in a futile attempt to kill her. Thoroughly maddened by the revelations, Tenshou keeps desperately firing at Yukari, who keeps toying with him until her abilities are fully unchained and promptly has him sucked him in one of her gaps.


* ''WebVideo/UndertaleTheMusical'' elaborates on [[spoiler:Omega Flowey's]] canon one during "[[https://youtu.be/z5yxcwrQkgY Your Best Nightmare]]" by making the last half of the song him becoming more frantic and desperate in [[ThisCannotBe disbelief]] as the [[spoiler:human souls rebel and turn on him.]]

* There's a [[http://www.fanfiction.net/s/5467423/1/WALLY_The_Novelization_Humanized fanfic]] that takes the film ''WesternAnimation/WallE'' and humanizes all of the characters. At the appropriate point, AUTO's breakdown becomes a much worse version of the one in the original film, since he's an indoctrinated officer, bent on following orders completely. He isn't sane to start with, and seeing the orders he was raised to follow being broken isn't very good for temper and mental health. Humanizing him made his breakdown much scarier.