* [[http://en.wikipedia.org/wiki/John_Siegenthaler John Siegenthaler]], a very respected journalist who signed onto ThatOtherWiki with the greatest of intentions, but singlehandedly ended up ruining it FOREVER. In May of 2005, some anonymous loser added some false information to his page that said that he was a suspect in JohnFKennedy's assassination. This error went unnoticed for five months. Then, someone informed Siegenthaler of the error. He created an account on Wikipedia to correct it, but the administrators didn't realize his intentions and kept reverting his corrections; they eventually blocked him. Also, by editing the article, he was in violation of [[http://en.wikipedia.org/wiki/WP:COI the Wiki's Conflict of Interest guidelines]], which specifically prohibit people from editing articles about themselves or people close to themselves. Eventually, a shitstorm went down that led to the creation of several controversial Wiki policies, including [[http://en.wikipedia.org/wiki/WP:BLP Biographies of Living Persons]], [[http://en.wikipedia.org/wiki/WP:Oversight the Oversight feature]] (and its very first use was on the Siegenthaler article!), and registration being required to start new articles. Most haters of Wikipedia say this was when the wiki JumpedTheShark. And all John Siegenthaler wanted to do was correct an error. Nice job breaking it, hero!
** Ironically, Wikipedia Watch, a site that Wikipedia is at war with due to its webmaster posting personally identifying information about its editors, ended up being the hero in this controversy by giving Siegenthaler personally identifying information about the guy who added the false information in. So, this controversy is also an example of NiceJobFixingItVillain!
** Such things were bound to happen from the very premise of the game. It's like spilling heaps of oiled sawdust all around the shop: one can always blame a smoker who walked by at night and didn't read the sign in big letters on the other side of the building, but dismissing any thoughts about fire safety made the result simply a matter of time.
* In ''HappyTreeFriends'', Splendid appears to be incapable of ''not'' doing this.
* During one campaign in the ''GlobalGuardiansPBEMUniverse'', the [[YourTerroristsAreOurFreedomFighters "ape-liberation" terrorist group]] Prime 8 attempted to detonate a high-yield nuclear weapon in downtown Paris. The Global Guardians stopped the simian supervillains... but during the course of the battle the ''heroes'' managed to knock down the Eiffel Tower (which, in turn, destroyed several square blocks of the city during its collapse). Oops!
* ''Website/{{Cracked}}.com'' article ''[[http://www.cracked.com/article_18684_6-movie-heroes-who-actually-made-things-worse.html 6 Movie Heroes Who Actually Made Things Worse]]'', about heroes who [[DepartmentOfRedundancyDepartment heroically]] tried to stop villains and ended up making things ''worse than if they did absolutely nothing'' (''Film/InglouriousBasterds'', ''Film/TheRing'', ''Film/{{Kick-Ass}}'', ''Film/ConAir'', ''Film/HarryPotterAndTheSorcerersStone'' and ''Film/{{Avatar}}'').
** In the same vein, ''[[http://www.cracked.com/article_18658_6-movie-plots-that-could-have-been-solved-in-minutes.html 6 Movie Plots That Could Have Been Solved In Minutes]]'' has example of heroes making too much troubles for themselves and/or their allies when doing nothing at all (''Film/RaidersOfTheLostArk'', ''Film/HarryPotter and the Goblet of Fire'') or the most mundane and trivial thing imaginable (''TheDaVinciCode'', ''Film/IRobot'', ''{{Saw}}'', ''Film/NewMoon'', ''Film/{{Return of the Jedi}}'') would ''obviously'' work better.
* [[DeadEnds Eddie]] accidentally [[spoiler:shooting Ephram's two remaining son's while in a daze which in turn causes his RoaringRampageOfRevenge.]]
* ''WebVideo/DoctorHorriblesSingAlongBlog'' features this trope writ large. Dr. Horrible is an IneffectualSympatheticVillain who is unable to follow through on any of his grandiose plans for world domination and is repeatedly humiliated by his ArchEnemy, JerkJock Captain Hammer. But when Hammer goes to far as to steal his would-be girlfriend, he makes [[ItsPersonal it personal]] and gives Horrible a reason to get serious. When Hammer tries to kill Dr. Horrible with his own damaged DeathRay, it explodes, injuring the hero and revealing his TrueColors as a MilesGloriosus, and [[spoiler:killing Penny]], breaking Horrible's MoralityChain and making him a true supervillain.
** It's also shown in the prequel comics that the anti-intellectual insults Justice Joe flings at the MadScientist villain he's fighting are why Dr. Horrible decided to switch from admiring the heroes to becoming a villain in the first place.
* [[WebVideo/AtopTheFourthWall Linkara's]] "Lord Vyce" story arc ended with this. Long story short, the Earth is being threatened by the feared intergalactic conqueror [[BigBad Lord Vyce]], who claims he conquers worlds to "protect" them from being invaded by [[EldritchAbomination a much greater threat]]. Linkara and his nakama defeat Vyce, strip him of his weapons and leave him stranded on a desolate planet. At the episode's end, we see that the evil entity Vyce spoke of is ''very'' real--and now that Vyce is out of the picture, it's free to roam in our reality.
** It's worse than that: Linkara has [[CosmicHorrorStory the entity's sacred tome]] in his possession, and he casually and routinely ''rattles off passages from it during his reviews.'' He didn't just leave our world vulnerable to attack from an Elder God--he might have '''''unleashed it!'''''
* ''SuburbanKnights'': The Cloaks, the obstacles, and [[spoiler: Jaffers]] are actively trying to stop the reviewers from finding the Gauntlet. Turns out they had a good reason to do so. [[spoiler: Malachite was tracking Team 2's map, meaning that he wouldn't have found the gauntlet in the first place if the reviewers hadn't gone looking for it.]]
** This spills over [[TwoPartTrilogy into the following special]], ''ToBoldlyFlee''. If the reviewers hadn't gone looking for the gauntlet then [[spoiler:[[CaptainPlanet Ma-ti]]]] would not have died, and subsequently would not have [[spoiler:merged with the Plot Hole]]. In doing so, [[spoiler:Ma-ti]] sets off an entire chain of events that leads to [[spoiler:the deaths of TheLastAngryGeek, [[StarWars the Emperor]], [[Film/SupermanII Zod]], [[Film/BattlefieldEarth Terl]], and [[WebVideo/AtopTheFourthWall Mecha-Kara]]]].
* In ''Literature/PayMeBug'', the protagonist has some security forces pinned in a stairwell; that is, until he mentions that he only has one pistol in a voice loud enough for them to hear him.
* In the WhateleyUniverse, uber-mage Fey has stopped the Necromancer three times and defeated the supervillainess Hekate. Only just recently have we learned that every one of these battles has caused Fey to draw enough life energy from ley lines that she has caused ''ecological disasters'' each time. Oops.
** During the Birthday Brawl, Bladedancer gets word from the Tao that the hostage situation to which she and Generator have been called will resolve itself without anyone getting hurt as long as nobody tries to go inside and intervene. Bladedancer and Generator are perfectly happy to just sit around and wait, but one of the local superheroes, a moron who doesn't respond to the police trying to flag him down, decides to charge right in and everything goes to hell.
* In the GrandFinale of ''[[DNAKpts4tv Death Note The Abridged Series (Kpts4tv)]]'' the Shinigami suggest [[spoiler: they were going to kill L [[HeKnowsTooMuch for knowing too much]] but Light beat them to it.]] Oh and Light was going to [[spoiler: kill Matsuda and stop the Shinigami invasion that would leave the Earth as a giant craphole but Matsuda shoots him up before he can.]]
* ''Series/{{Noob}}'':
** Season 2 finale: [[spoiler:Omega Zell tries to use a hacker-made item to quickly kill the enemys of Justice, the guild he dreams of joining. The problem is that the item works in a completely random way and all it ended up doing was erasing the avatar of Justice's top player]].
** Season 5 finale: Roxana keeps Saphir from ending a major quest so the Justice guild doesn't get the honors that go with its success. The quest's purpose? Keeping the game's BigBad who's antagonistic to all player factions from gaining more power.
* ''Machinima/TeamServiceAnnouncement'':
** In ''[[http://www.youtube.com/watch?v=VuvE3y4LspE Ranged Combat]]'', just as the RED Sniper Jarated the BLU Spy, his Heavy, Soldier and Scout teammates all pose as snipers, confusing and scaring off said BLU Spy. Then when the Sniper tried to get a clean kill off the running Spy, his focus got broken by the teammates trying to shoot the Spy with their short range weapons, allowing the Spy to run free. That really pissed the Sniper off.
** In ''[[http://www.youtube.com/watch?v=DfizLF4-Pdo Subtlety]]'', the BLU Spy is about to land a backstab on the RED Heavy... only for the BLU Scout to rush forward and start whacking the Heavy with a frying pan. [[UnstoppableRage The Heavy is not pleased]], and neither was the Spy.
* At the end of ''WebAnimation/{{Ducktalez}} 3'', Vegeta is defeated by being thrown into the sun, which explodes the sun and covers the world in eternal darkness. Nobody seems to mind though. Every Ducktalez since then takes place at night.
* WebVideo/ReZonanceSoundtrackReviews: Izumi, the NonHumanSidekick to the show's host, ReZ, has not only unintentionally made ReZ go [[FreakOut temporarily crazy]] and give him LaserGuidedAmnesia due to an game she gave him, she also caused him to [[JourneyToTheCenterOfTheMind become trapped in his own mind]] [[ItMakesSenseInContext just by talking to him while inside his mind.]]
* In ''WebAnimation/DusksDawn'' Star Whistle caused a storm that ravaged Ponyville.