%% This list of examples has been alphabetized. Please add your example in the proper place. Thanks!
%% Image removed per Image Pickin' thread: http://tvtropes.org/pmwiki/posts.php?discussion=1516305528067720900
%% Please start a new thread if you'd like to suggest a new image.
!!Web originals with their own pages:
* ''MoralEventHorizon/SuperMarioLogan''

* ''Website/AlternateHistoryDotCom'' has several examples:
** In ''Literature/{{Reds}}'', [=MacArthur=]'s [[DayOfTheJackboot counterrevolution]], which included letting Klansmen run wild across the South, and assassinating Huey Long, and the Louisiana State Legislature, all because the Communists won a fair election. In-universe, this is what triggers the Second American Revolution.
** In ''Literature/TheAngloAmericanNaziWar'', [[spoiler:Acting Fuhrer Himmler]] crosses this when he issues Order 571, which has German forces destroy several culturally-significant cities, thousands of years of irreplaceable history, [[IfICantHaveYou in preference to allowing the Allies to have them]]. [[spoiler:This includes a thorough destruction of Paris, ''which is televised to Britain'']]. [[EvilIsPetty Modern historians in this universe compare the Nazis' actions to a jealous, bitter ex-spouse squirreling away some assets and then ruining everything they can get their fingers on]].
** In ''Literature/AsOneStarSetsAnotherRises'', there are potential candidates for when the Third Reich first crossed it. They massacred Jewish civilians in Poznan and Berlin, but if not then, they all but crossed it when they [[spoiler: bombed a German town with a ''radium-laced bomb'', just because the French occupied it, killing and poisoning tens of thousands]].
*** [[MoralGuardians Movement for Traditional America]], despite having knowledge about the Holocaust, continued to lobby Congress to stay out of the Holocaust. If that wasn't bad enough, [[spoiler: several members of the MfTA try to start a race riot in Futureville during a bigoted protest, even killing a police officer]].
** In ''[[spoiler: Rumsfeldia]]:Fear and Loathing in the Decade of Tears'', the sequel to ''Literature/FearLoathingAndGumboOnTheCampaignTrailSeventyTwo'', it is hard to know when [[spoiler: [[PresidentEvil Donald Rumsfeld]]]] sails over the line, but there are some things: killing[=/=]disappearing political opponents, [[spoiler: using voting fraud to win the 1984 election]], ripping all forms of worker's rights and environmental regulation, giving military aid to [[AmoralAfrikaner Magnus Malan]]. [[spoiler: But the worst moment is when Liberty Legions are ordered to kill wounded soldiers so as to not pay for their welfare]].
** ''Literature/AWorldOfLaughterAWorldOfTears'': [[InUniverse In the eyes of the African American community]] is when [[spoiler: white racists brutally murder Ernest Green of the Little Rock Nine]]. After that, the nonviolent Civil Rights Movement collapses, and black Americans start engaging in terrorism. [[spoiler: Another line is when the Florida police commit a massacre against the black community in Tampa. [[EvenEvilHasStandards Even the Soviet Union thought the Florida State Government should be prosecuted for war crimes]]]].
** ''Literature/TwilightOfTheRedTsar'': Joseph Stalin was already over the line, OTL. But he goes even further than OTL when he begins his own Holocaust of the Soviet Jews, which later expands into a Baltic Holocaust. [[spoiler: And then he completely obliterates the People's Republic of China in war, unleashing biological weapons and nuclear bombs]].
** ''WebOriginal/ZhirinovskysRussianEmpire'': Vladimir Zhirinosvky and the UIS jump around horizon several times, with genocide, political repression, and international thuggery. But [[InUniverse the specific moment]] when the world community realized how insane Mad Vlad was when he sent a letter to Helmut Kohl, proposing a ''joint Nazi-style invasion of Poland'', followed by locking Poles in concentration camps, and later organizing attacks on the German, Israeli and Polish embassies.
* ''WebVideo/AtopTheFourthWall'':
** Mechakara firmly crossed it when he [[spoiler: tried to [[DrivenToSuicide drive Linkara to suicide]] (and it was ''not'' PlayedForLaughs), by making him think he was [[AbusiveParents the father]] of the girl who was turned into his magic gun.]]
** [[spoiler:Holokara pulled an extreme FaceHeelTurn and drove over the horizon in a single move, when he ''[[AxCrazy threatened to kill '90s Kid]] if he ever [[DisproportionateRetribution interrupted the show again.]]'']] Definitely '''not''' PlayedForLaughs.
** [[spoiler:Later, he threatens to maim Harvey Finevoice when Harvey calls him out for threatening to kill '90s Kid. Specifically, he casually threatens to crush the singer's vocal chords.]]
** [[spoiler: Lord Vyce]] crosses over when he [[spoiler: [[MindRape Mind Rapes]] NIMUE, forcing Linkara to delete her. At this point, we can pretty much drop the "Anti" part of AntiVillain.]]
--->'''NIMUE:''' ''You are'' '''''evil''''' ''[[spoiler: Vyce]]. You are cruel and unjust.''
** And even if there was a shred of decency left for [[spoiler:Vyce]], since it turns out [[spoiler:the Entity was still alive and he was being ProperlyParanoid]], he irredeemably crosses the line again when [[spoiler:he tried to pull the Earth into a dimensional portal, thinking the Entity's VillainousBSOD was another trick.]]
* ''WebVideo/BadCreepyPasta''
** The gang [[DiscussedTrope discuss]] this trope in their riff of ''Jeff the Killer Vs. Michael Myers'', when [[FatalAttraction Jeff the Killer and Jane the Killer start making out,]] ''[[CanonDefilement despite being mortal enemies.]]'' Jacob points out that it seems very unlikely that Jane would have been able to even ''forgive'' Jeff for [[YouKilledMyFather killing her friends and family]] and [[KillItWithFire lighting her on fire]] back in ''Jane The Killer: The Real Story'', let alone make out with him. [[OneOfUs They even reference the term "Moral Event Horizion"!]] [[note]](Then again, due to the lack of a firm Jeff The Killer canon, it's possible the author of ''Jeff the Killer Vs. Michael Myers'' never read ''Jane The Killer: The Real Story'', but still...)[[/note]]
** Interestingly, Jacob considers the ''author'' of ''Dating Game'' to have crossed the line when he [[spoiler:had the SerialKiller wife [[WouldHurtAChild kill off her two sons]] (one of whom was an '''infant''') in horribly gruesome ways [[StuffedInTheFridge just for shock value]]]]. After reading about this, he angrily refuses to read any more of the story (leaving his cohorts Matt and Toby to finish it), and [[TheReasonYouSuckSpeech gives the author one of the show's most brutal verbal beatdowns at the end of the episode]], in a tone dripping with nothing but pure, [[TranquilFury calm]] '''''hatred''''' (in stark contrast to the comparatively gentle ribbing of the story from the beginning of the episode).
* WebVideo/BennettTheSage goes into discussion about this in his ''[[Anime/NeonGenesisEvangelion End of Evangelion]]'' review, in regards to the opening minutes. He discusses how it can make an effective AntiHero, but in Shinji's case it was just... well let's have Shinji describe it.
-->'''Shinji:''' I'm so fucked up.
* ''Roleplay/DinoAttackRPG'':
** In an interesting case, Rotor somehow crossed his moral event horizon and actually managed to return. Exactly when it happened is debatable, whether it was his KangarooCourt or later the fact that he [[TortureAlwaysWorks tortured a child]] via NoHoldsBarredBeatdown. Either way they both seemed to show that he was irredeemable... at least until he got his act together during the final battle.
** Michelle Glados's intentions to kill everyone ForScience.
** The team is fighting for their lives in a FinalBattle, and [[DirtyCoward Snake deserts them to save his own skin]]. That's bad enough, but then he actually ''pauses'' in the middle of his escape, sees a Dino Attack agent who was already badly wounded, ''kicks the agent while he's down'' because that agent ''[[ProtagonistCenteredMorality supposedly]]'' stole stuff from him [[NoodleIncident in the past]], and then leaves said agent to die alone in the streets of a Mutant Dino-infested city. WhatTheHellHero
* WebVideo/DoctorHorriblesSingAlongBlog has an odd example, as the 'hero' of the story passes his before the villain does. Furthermore, he is responsible for the villain's MEH. Captain Hammer's is viewed by many as [[spoiler: bragging to Billy that he is going to sleep with Penny solely because he knows Billy has a crush on her.]] However, if this doesn't qualify, his decision to [[spoiler: use the Death Ray on Dr. Horrible in a room full of innocent people definitely does. This results in Penny's death, which tips Billy over the edge.]]
* In the ''Roleplay/GlobalGuardiansPBEMUniverse'', the [[OmnicidalManiac Blood Red King]] is the AnthropomorphicPersonification of Cruelty and Malice, and as such he came into being already well past the MoralEventHorizon. His worst act to date was walking into a hospital in Amsterdam and killing every doctor, nurse, patient, administrator, janitor, visitor, and newborn infant whose last name began with an "odd numbered letter" (A = 1, B = 2, and so on), leaving the rest alive and traumatized. Why did he do this? [[ButForMeItWasTuesday Because he was bored on a Wednesday]].
* WebAnimation/EddsWorld has Tord, the beloved Norwegian GunNut, finally come back after 8 long years of absence, and what does he do? [[spoiler: Blow up Edd's house, almost kill Tom, [[KillTheCutie kills Jon]], and [[ArsonMurderAndJaywalking punches Matt in the face]].]]
* ''WebVideo/TheIrateGamer'':
** The Gamer [[DesignatedHero himself]] murdering Kool-Aid Man for doing what he does on Christmas.
** In the ''Franchise/StarTrek: 25th Anniversary'' review, he kills [[RedShirt Lieutenant Drunkard]] by beaming him down onto Apandana, a planet with gaseous atmosphere. [[DisproportionateRetribution All because he was insulted.]]
--->'''[[http://irategamersucks.blogspot.com/2013/05/my-sensors-indicate-massive-amounts-of.html BatDanNight]]:''' Holy shit! That was needlessly cruel! I know the character was annoying and I even predicted he would die (red shirt) but I didn't expect it to be that awful! I thought it would be a Gorn or a Klingon or something. [[WhatTheHellHero You're the hero! You’re not supposed to do this!]]
* ''WebOriginal/JeffTheKiller'':
** Jeff crosses the point of no return by killing his entire family.
** The TerribleTrio responsible for his StartOfDarkness, Randy, Keith, and Troy, crosses it by attacking Jeff at a party and threatening to shoot the party goers if they try to stop them from killing Jeff.
* Alex in ''WebVideo/MarbleHornets'' was always a bit unhinged. Breaking Tim's leg, refusing to tell Jay anything, lying to everyone he knows. But the line was crossed in Entry #49 when [[spoiler: he murdered an innocent man just checking to see if he's okay, believing it was Jay following him. He then has The Operator dispose of the body.]] No hope now. Entry #51 reveals [[spoiler: he's been doing it for years, even back when he was making the original Marble Hornets movie.]] Even then, [[spoiler: Alex's motivation was questionable, due to the possibility of The Operator [[BrainwashedAndCrazy being around his entire childhood.]]]] However, [[spoiler: Hoodie/[[TheReveal ToTheArk]] really went JumpingOffTheSlipperySlope in Entry #61, where he sabotages Tim's medication and causes him to revert back into Masky.]] Damn.
** Later entries paint a new light on [[spoiler: Hoodie's situation, and reveal that he is stealing Tim's meds not because he wants to hurt Tim, but because ''he needs it'' just as much as Tim does, and must resort to stealing. This guy is just as vurnerable to The Operator as the others.]]
* ''WebVideo/TheMusicVideoShow'' has the host being told he [[spoiler:killed his parents.]] in the last episodes of season 2. The screams heard in the last episode of season 1 MAY be the sounds of [[spoiler:his parents screaming while they're being killed]] as opposed to people screaming because it 's the end of the world.
* In the ''Roleplay/NewDawnAcademy''-verse, there are truly many depraved villains, but none of them cross the line like these loons:
** Grahf Mordes, sacrificing his family for power. What really sealed it was his reaction to their screams and cries of "Why?" ''He merely laughed''.
** Qord was pretty insane before, but what made it really, really clear he was utterly morally repugnant was his teleporting in a young police officer just out of academy and telling an assembly of young magic users to torture the officer to death as they see fit, when he is viewed by the magic users as a teacher. What sealed the deal in this case is when the cop, in a nod to ''Film/ReservoirDogs'', says he has a family waiting for him at home, Qord tells him that makes it all the better. Even the other Esoterica Higher Ups were sickened. Yes, even [[GeneralRipper Zenobia]].
* ''Website/ThatGuyWithTheGlasses'':
** ''WebVideo/TheNostalgiaCritic'':
*** In the Conquest of the Commercials where the Critic was glad of on the ''[[VideoGame/{{PokemonRedAndBlue}} Pokémon: Red and Blue]]'' of the bus driver is crush many Pokémon monsters at the garbage crusher, but later the bus is turned into a Gameboy causing Critic angered that he edited the scene is [[Main/BadPeopleAbuseAnimals crushing to death at the Pokémon monsters]] and even [[Main/CrossesTheLineTwice insulting the fandom where they crying in the background]]. Later Critic is use to [[Main/RunningGag keep insulting the ''Pokémon'' series throughout the episodes]].
*** During in ''Film/FreddyVsJason'' review where Critic is testing the crossover battle, one of the infamous part is he test [[Anime/{{Pokemon}} Ash Ketchum and Pikachu]] battle against [[Franchise/EvilDead Ash Williams]] [[spoiler:but until that Williams chainsaw at Pikachu while Ketchum is protect himself as a shield, later Ketchum is crying of beheaded Pikachu when Critic yelling at Ketchum to "suck it up" and Ash Williams said "[[VideoGame/PokemonGo Pokémon Go]] fuck yourself"]].
** ''WebVideo/TheNostalgiaChick'':
*** Parodied in-universe by Dark Nella Saga. The Chick only realizes Dark Nella is evil when she finds that Minnesota's big ball of twine has been destroyed. Oh no!
*** With the Todd storyline, Chick became a concretely psychotic stalker at one of three instances. Either forcing him regularly to be her CaptiveDate, being too happily willing to rape him, or preying on his money insecurities to make him do a review with her; take your pick.
* William Shaw in ''Literature/{{Paperwalls}}'' crossed this when he raped his daughter Cameron, and kept finding new moral event horizons to cross.
* The [[NoNameGiven mysterious]] [[EvilSorcerer mage]] of ''Literature/TheQuestportChronicles'' jumps straight across when he [[spoiler:destroys Questport]]. To make matters worse, the heroes still aren't sure ''why'' he did it.
* ''Wiki/SCPFoundation'':
** "[[http://scp-wiki.wikidot.com/scp-590 SCP-590]] is not to be named as anything other then Five Ninety. He is a tool to be used, not someone's friend, sibling, or child. Anyone found forming attachments to an SCP will be removed to a less people-intensive duty." A teenage boy who has the power to heal any human ailment by touching someone and taking the ailment to himself. The way the Foundation took advantage of this is infecting him with mental retardation to keep him pliable. Where they ''really'' cross the MoralEventHorizon is that [[spoiler:the person who suggested it, Dr. Bright, is ''his older brother.'']]
** There's also SCP-231-7 and the containment process for her, 110-Montauk, which is [REDACTED]. It's so horrible that anyone who performs it gets mind-wiped (if they don't commit suicide first)... [[AndIMustScream and then they do it again]]...
** Even worse, this is a NecessaryEvil ([[EvenEvilHasStandards They don't want to preform the procedure on SCP-231-7]], but she will give birth to a [[EldritchAbomination monster that is said to bring forth the end of time]] if they don't). The Foundation doesn't really believe in a MoralEventHorizon.
* Various villains in ''Roleplay/SurvivalOfTheFittest'' cross this line at some point:
** Cody Jenson was already a dick before, but after his rape and murder of Madelaine Shirohara, followed by killing Amanda Jones while trying to kill Sidney Crosby, the SOTF community in general rallied behind Adam Dodd, whose TrueCompanions the two girls were part of, to kill him.
** Adam Reeves manages to cross this line in his very first appearance, after raping Maxie Dasai.
** After killing 5 people, Reiko Ishida still managed to cross this line after killing defenseless girl and only living friend, [[spoiler:Carol Burke, after Carol said she wasn't as strong as she thought she was.]] DisproportionateRetribution much?
*** It also turns out to be an in-universe example; When Reiko comes across her girlfriend Sarah Xu and [[spoiler:attempts to get on the escape boat with her, she is denied access to the boat by STAR, who then proceeds to use, among other things, the above incident for a reason why.]] It results in [[spoiler:Sarah and Reiko being separated]]. [[HeelFaceDoorSlam Ouch]].
** Maxwell Lombardi strangling Augustus [=MacDougal=], shooting Harold Fisher, and gloating to the cameras that there was more where that came from. [[FromBadToWorse Which there was]].
** Alex White crosses the line with his [[spoiler:slow, torturous killing of Rosa Fiametta]].
** Aaron Hughes crosses it, but most agree that [[spoiler:leaving Tom Guthrie to die at the hands of Nick Reid and then claiming he died to protect the group]] very early on in the game was quite cruel and confirmed the character to be a ManipulativeBastard in most handlers' eyes.
** Marvia Jones in SOTF-TV managed to cross it in her first in-game appearance, when she comes across a traumatized Nate Chauncey. She then proceeds to give her ecstasy (which she tells her is a headache pill) and take advantage of her sexually. It culminates it her calling Nate a whore for accepting her advances, beating her up, and stealing most of her supplies, including her clothes.
* ''WebVideo/ThereWillBeBrawl'':
** Of all people, ''Princess Zelda'' crossed this when she [[spoiler: stabbed Link in the back just as he was making a HeelFaceTurn, then in the next episode revealed that she had been working with Gannondorf the whole time. Not even attempting to [[TakingTheBullet take the bullet]] for Link redeemed her, really.]]
** Wario. [[spoiler:He orchestrated a Pikmin Bomb to take out Red (the only indisputably ''good'' character in the series, got his mentally challenged brother to deliver the bomb, and then tried to pay Red's girlfriend off with money (and that was a lie; he had planned to kill her too).]]
** Kirby crosses this in the backstory when he gruesomely murders Daisy.
* Throughout ''WebVideo/ToBoldlyFlee'', the Executor is a sleazy, manipulative, creepy BadBoss and MagnificentBastard, but he is hammy. But then he tortures a helpless Luke (one of the youngest members of the site) with his electricity powers and you wants him to die painfully. [[spoiler:Thankfully he does]].
* WebVideo/UltraFastPony
** [[spoiler: Twilight ''murdering Pinkie Pie'', simply because she annoyed her, before blasting away all her clones and just keeping the last one as her replacement, is either this or CrossesTheLineTwice.]]
** Spitfire abandoning her own daughter for ten years, while telling her husband she was dead, only to bring her back, just to make Rainbow Dash jealous.
** Also, [[spoiler: Rarity murdered '''babies''' to get material for a fashion show.]]
* ''Roleplay/WeAreOurAvatars'':
** [[Series/PowerRangersLightspeedRescue Carter]]/[[GenderBender Catherine]] doesn't just cross this after becoming a Team Rocket member, s/he leaps directly over it, starts running, and never looks back. This eventually leads to his getting kicked off the team and re-defecting to the rest of the group.
** [[VideoGame/MegaManBattleNetwork Duo]] mentions an incident with Slur involving seven planets being destroyed, he notes that 5 of those planets may not have been infected with Evil Energy in the first place, and that Slur may have done it just because she could.
** Cyber Amy(A.K.A. Amy being fused with her father Deviot's soul) rapes [[Webcomic/EightBitTheater Black]] [[TheChewToy Mage]].
** Deviot revived Kasei. Worked out till Saturn's version of Him decided to give Kasei his power back.
* ''Literature/WhateleyUniverse'':
** MadScientist Emil Hammond quickly demonstrates that despite his claims that he works ForScience, his real motivation is sadism. For that matter, the Goodkind family pretty much crossed their MEH right at the start, by handing Trevor over to Hammond to be experimented on in the first place.
** Don Sebastiano and Hekate had already crossed their MoralEventHorizon before the series even began, when they mentally enslaved Cavalier and Skybolt and used the mystery about why the two former would-be heroes were suddenly sycophants of such obvious villains to terrify their opponents and push their way to the top of the school's social pecking order. Just how deep they had gone is only fully revealed when Hekate tried to trap Fey in the same manner. [[spoiler: Hekate, in particular, was found to have practiced HumanSacrifice on several occasions, killing children to offer their souls to demons. Don Sebastiano, meanwhile, gleefully [[RapeIsASpecialKindOfEvil used both Skybolt and Cavalier as sex toys]] and punching bags [[ForTheEvulz whenever it amused him]] to do so.]]
* [[DiabolicalMastermind Coil]] from ''Literature/{{Worm}}'' was established as a villain from the get-go, what with him planning to take over Brockton Bay for no other reason than his own ego. What ''really'' pushes him across the line, though, is when he kidnaps a twelve-year-old girl with precognitive powers so he can use them to aid his plan, [[WouldHurtAChild drugging her heavily to keep her complacent and forcing her to use her power despite knowing that it causes her great pain]].
* In the LetsPlay/{{Yogscast}} [[Machinima/YogscastMinecraftSeries playthrough of]] ''VideoGame/{{Minecraft}}'', this has come up a number of times despite the BlackComedy.
** From ''Shadow of Israphel'':
*** The titular antagonist crossed the line either when he destroyed [[spoiler:the Yogcave]] or when he zombified [[spoiler:Granny_Bacon, forcing LetsPlay/LewisBrindley and LetsPlay/SimonLane to put her down, later bombing her funeral]]. The latter is often cited by fans as his point of no return.
*** [[spoiler:Jock_Fireblast]] crosses the line when he burns down [[spoiler:Mistral City]].
*** [[spoiler:Skylord_Vitali]] murdering his comrades in increasingly brutal, gruesome and nightmarish ways also counts, all for the sake of power.
*** [[spoiler:King_Finbar]] crossed the line when he zombified his own subjects, even those loyal to him.
** From LetsPlay/{{Sjin}}'s "Feed the World" series, eventual KnightOfCerebus Strawfingers is revealed to have crossed the line through CerebusRetcon, when it turns out he murdered [[spoiler:Abel's parents]].
** The ''Yoglabs'' series by and large revolves around a MadScientist group experimenting, but there are nevertheless some particularly horrendous moments that are taken deadly seriously.
*** Gozencrantz and Rildenstern cross the line when they [[spoiler:murder Simon's master clone in an effort to take over Yoglabs]].
*** As of "Block Gun Mod", Lewis appears to have crossed the line by [[spoiler:ordering Simon to blow up a village of Testificates with the weaponry from the titular mod]]. The tone of his voice implies that [[spoiler:unlike previous efforts, the villagers are sentient and it isn't just a simulation like before]]. This causes Simon to [[spoiler:blow up a large chunk of the lab and try to free some trapped commandos that were insane, though he gets himself and most of the hostages killed in the attempt. Due to the cloning system, Simon doesn't remember this]].
** In Duncan and Kim's series "Flux Buddies 2.0" [[spoiler: [[EvilTwin Lalnable Hector]]]] crosses the line [[spoiler: by [[KickTheDog murdering all of Duncan and Kim's Chocobos bloodily for no reason.]]]]
%% This list of examples has been alphabetized. Please add your example in the proper place. Thanks!