->''"In a situation that's already a powderkeg, one doesn't ignore the man handing out matchbooks."''
-->-- '''[[http://freefall.purrsia.com/ff1400/fc01340.htm Florence Ambrose,]]''' ''Webcomic/{{Freefall}}''

Someone unintentionally plays a [[SmallRoleBigImpact small and/or unlikely but crucial role]] in some horrible development (usually this action serves as the catalyst). It may be a simple and perfectly rational observation, but it still counts as TemptingFate.

An Unwitting Instigator of Doom can be basically complicit with the villain, but in that case, they're generally seeing only a small portion of the picture. If they're being specifically manipulated but do not realize, they're an UnwittingPawn. Other times, they're simply blundering in like a [[SpannerInTheWorks wrench in some particularly highly valued machine]]. They may also end up as the IdiotHoudini. In other cases, more GenreSavvy or simply in the know characters will [[WhatTheHellHero chew them out]] for bumbling in and screwing things up, trusting them little better than they would a traitor.

Compare NiceJobBreakingItHero for when the heroes cause doom, and MikeNelsonDestroyerOfWorlds for a different type of unwilling doom bringer. Also compare ChekhovsGunman, in which a seemingly insignificant character becomes more important later on. See also InterruptedCooldownHug, EndangeringNewsBroadcast, TragicMistake, SmallRoleBigImpact.


[[folder:Anime and Manga]]
* ''Franchise/DragonBall'':
** In ''Manga/DragonBall'', [[HarmlessVillain Emperor Pilaf]] releases [[SealedEvilInACan Demon King Piccolo]], who promptly proceeds to [[HeroKiller have many of the world's leading martial artists killed]], including Goku's best friend, Krillin, and nearly takes over the world. Pilaf hopes to be able to be rewarded by Piccolo with his own territory, only to be backstabbed. Nice job nearly dooming the world, shorty.
** However, in releasing Demon King Piccolo, not only did Pilaf ensure that Goku would grow up to be a warrior trained by God himself, and thus be powerful enough to put up a fight (with the reborn Piccolo) to kill Raditz, then get training from Kaio-Sama to defeat Vegeta, later accidentally recreate the Super Saiyan transformation to defeat Frieza, defeat Cell who was created by Gero in retaliation for the destruction of the Red Ribbon Army (which happened a while before Pilaf freed Piccolo) and would have wiped out humanity had it not been for Goku training Gohan, and then finally defeat Majin Buu. In short, had it not been for Pilaf, humanity would have been enslaved by Raditz, the Earth would have been sold to Frieza, Cell very likely would have wrought havoc on the universe then, until Babidi revived Majin Buu who would have killed everything in the Universe... so, uh... [[NiceJobFixingItVillain "thanks for indirectly saving the Earth" Pilaf?]]
** ''Anime/DragonBallZ'':
*** Remember how Majin Buu became truly evil, killed off half of the Z-warriors, the entire human race, and then finally blew up Earth? It all happened because of a few goons in the episode "The Evil of Men", where they attack and shoot Bee (Buu's pet puppy) and Hercule (Buu's new best friend who was in the process of rehabilitating him). As a consequence Buu snapped and steamed out [[EnemyWithout Evil Buu]], who then [[SplitPersonalityTakeover proceeded to absorb him]]; the entire rest of the Buu saga is the ''entire universe'' paying the price for what those thugs did.
*** Goku letting Vegeta train first in the Hyperbolic Time Chamber. When Vegeta left the chamber to fight Cell, [[SmugSuper Vegeta is so arrogant in his new power]] that he allows Cell to become complete to stroke his own ego, which leads to the deaths of Goku, Trunks, and Android 16.
*** While Goku, by his own admission, could have killed the fat Majin Buu at Super Saiyan 3, he deliberately chose not to because he wanted to give Trunks and Goten a chance to do so and because he didn't want the next generation to think they could just depend on him all the time. Goku's inaction leads to the birth of Super Buu, leaving the remaining Z-Fighters with a far more powerful and dangerous enemy to contend with.
*** On another level, his holding back during the fight against Vegeta caused Vegeta to believe he could defeat Buu and led to his SenselessSacrifice. Vegeta makes sure to chew Goku out over this when he's semi-revived near the end of the Buu Saga.
*** There's also an inversion: [[spoiler: Had 18 just beaten Hercule outright instead of blackmailing him, he would have lost all credibility as a champion and would not have been in a position to aid Goku in making the Spirit Bomb by encouraging everyone to give their energy.]]
** It happens again in ''Anime/DragonBallZResurrectionF'', where Pilaf and his gang help bring Frieza back to life.
** ''Anime/DragonBallGT'': As revealed during the Shadow Dragon Saga, the Dragon Balls produce negative energy for each wish granted, which is stored in the balls for it to dissipate harmlessly over 100 years; in fact, the Dragon Balls scatter after every use because it's expected to take ''years'' to find one through conventional methods, thus allowing them to disperse the negative energy harmlessly. Unfortunately, that countermeasure was rendered completely useless when Bulma invented the Dragon Radar, allowing the Z-Fighters to find the Dragon Balls very quickly and summon Shenron numerous times, eventually leading to the birth of the Shadow Dragons.
** ''Anime/DragonBallSuper'':
** During the Future Trunks Saga, Goku, in trying to find out the identity of [[EvilTwin Goku Black]], travels to [[AlternateUniverse Universe 10]], where he meets Zamasu, a Supreme Kai apprentice who distrusts mortals and believes that TheGodsMustBeLazy for simply watching and doing nothing while they commit evil deeds; their subsequent sparring match ends up triggering Zamasu's StartOfDarkness. After seeing how Goku, a mere mortal, could become powerful enough to challenge the gods, Zamasu begins a downward spiral, going from simply distrusting mortals and seeing them as foolish to a full-blown JerkassGod who seeks to [[KillAllHumans wipe out all mortal life]].
** Zamasu's master, Gowasu, also ends up fanning the flames quite a bit to to several {{Advice Backfire}}s. It's ''his'' idea for Goku and Zamasu to spar, hoping that Zamasu would learn more about mortals and the experience would ease his distrust for them. Unfortunately, Goku [[UnderestimatingBadassery ends up being more powerful than he thought]], and the encounter only solidifies Zamasu's hatred of mortals and makes him obsessed with Goku. He then takes Zamasu to planet Babari so he can observe the primitive life there and see if they will become more civil after a thousand years, as well as teaching Zamasu how to use the Time Rings. While they've developed some culture after one thousand years, the Babarians are still quite barbaric, which only further convinces Zamasu that mortals are too stupid and dangerous to live. Finally, he [[spoiler: gives Zamasu the means and knowledge of how to implement his plan to kill off all mortals by having him watch the U6 and U7 tournament and telling him about the Super Dragon Balls.]]
* ''Anime/CodeGeass'':
** In season 2 [[TheDragon Schneizel]] makes a case to the Black Knights to surrender their leader Zero, who he reveals is his long-lost half-brother, Lelouch vi Britannia. While not without their doubts towards their leader based on some of his actions, they, at least counting the likes of Tamaki and Diethard, remain wary and skeptical towards Schneizel, who is rightfully suspected to be just as easily tricking them with the evidence and testimonies that he is presenting. Not more than a few moments later does Ohgi come along with his still secret love interest Villetta, a Britannian spy, with some additional cursory yet suspicious evidence the latter provided that leads everyone else amongst the Black Knights present into deciding [[KangarooCourt to turn on Lelouch without giving any chance of there being a case made in his favor]].
** This is significant in that afterwards, Lelouch [[DespairEventHorizon believes there is no turning back for himself given what he has already suffered in the past in addition to this]], and basically goes from a WellIntentionedExtremist who at least had a sensible blueprint for neutralizing Britannia and had gotten as far as setting up a legitimate international front to that end to [[TheUnfettered throwing away any last inhibition he had]], [[spoiler:and using a GenghisGambit of questionable necessity, evidently to fulfill a [[DeathSeeker death wish]]. A more peaceful final solution to the global conflict could have been arrived at that would have also resulted in Lelouch living on and not abandoning his loved ones, or making the questionable decision of leaving [[FallenHero Suzaku]] with the role of Zero]].
** Rolo and Jeremiah have huge instigating roles in ''R2''. First, Jeremiah [[spoiler: uses his Geass Canceller ''without checking his surroundings'' at some point, which accidentally causes him to undo Shirley's FakeMemories about Lelouch]]. Then, Rolo [[spoiler: is confronted by the memories-reset Shirley and, [[SayingTooMuch when she mentions Nunnally]], he both [[YanDere gets crazily jealous]] AND [[HeKnowsToomuch realises she knows stuff that would be VERY troublesome]], so he stabs her to death.]] Both of these actions prompt Lelouch to raid a camp where Britannia was preforming experiments to create more {{child soldier}}s like Rolo and pretty much kill everyone there... and had that not happened, [[ManipulativeBastard Schneizel]] wouldn't have as much evidence against Lelouch as he would, which would have prevented '''everything mentioned above'''.
* ''Manga/DeathNote'':
** Misa Amane does this twice, to the severe detriment of [[ALighterShadeOfGray both sides.]] Once, it's as a PoisonousFriend to Kira, [[spoiler:giving L physical evidence in the case in her sending the tapes]], and the other time, it's out of MadLove to same, [[spoiler:endangering her own life to the point that her shinigami has to intervene]]. For a fervent Kira supporter, she's really a bit of a loose cannon: she never seems to fully appreciate her role in either disaster.
** Sachiko asks her children to bring their father a change of clothes, and Sayu is reluctant to take the task. When Light volunteers, he ends up running into Naomi, learning about how close she is to figuring out an important part of how he kills people, and silencing her before she can reach L.
** Aizawa opens up his umbrella when it begins to snow and so ''just'' misses seeing Light and Naomi Misora together.
** Teru Mikami [[spoiler:breaks his "once-a-month-to-the-bank" routine after learning that Mello has kidnapped Takeda in order to dispose of any loose ends. However, he is unaware that Light has also done the same thing, making his actions unnecessary. But he managed to tip Near to the location of the ''real'' Death Note he was using, resulting in the failure of Light's final gambit and his downfall.]]
* [[SociopathicHero Mikazuki Augus]] from ''Anime/MobileSuitGundamIronBloodedOrphans''. Being a soldier who kills to survive and [[spoiler:avenge his friends]], Mika often takes ruthless solutions to deal with his enemies, however, his actions inadvertently contributed to Ein and Gaelio's StartOfDarkness and the CycleOfRevenge between them, namely [[spoiler:him [[MercyKill mercy killing]] Crank as well as dishing out an ExtremeMeleeRevenge towards Carta.]]
* ''Manga/{{Naruto}}'':
** Aoba Yamashir is a recurring background ninja who was probably never formally introduced, databooks aside. Why is his name so well-known in some parts of the ''Naruto'' community? A single careless sentence out of Aoba's mouth revealed Itachi's whereabouts and goals to Sasuke. Following that, Sasuke tried to beat up Itachi, was soundly defeated, and pondered why Itachi would be interested in Naruto. Sure, Sasuke wasn't particularly stable before, but this huge blow to Sasuke's self-esteem was the catalyst for the event that would finally send Sasuke over to TheDarkSide.
** Kakashi, ''of all people''. [[spoiler:He speaks about Naruto's birth at Rin's grave, and it just ''so happens'' that Tobi/Obito happened to overhear it, resulting in ''the Nine-Tailed Fox's fateful attack'' and the death of the Fourth Hokage]]. Furthermore, had Kakashi not [[spoiler:abandoned his principles and went back to help Obito save Rin, then Obito would have died. If Obito had died then, then Naruto's parents would still be alive, Naruto wouldn't have been marginalized by the village in his youth, Nagato would have been less crazy, the Rain Village wouldn't have committed as much genocide, Madara's plan would have died with him, the Jinchuriki would still be alive, the Uchiha Massacre might have been stopped, the Fourth Great Shinobi World War wouldn't have happened, and the Ten Tails wouldn't have been revived to wreak destruction upon the world.]] When Kakashi realizes this, he [[DespairEventHorizon logically isn't happy.]]
** Jiraiya took pity on three Rain Village orphans and trained them. They grow up to be revolutionaries in their own village, and after [[spoiler:Yahiko dies, Nagato turns evil, helps form Akatsuki with Tobi/Obito and Konan, and becomes an enemy of the Leaf Village, killing Jiraiya and devastating the village.]] But to be fair that only happened cause of the guy right below...
** Danzo does this quite a bit. He means well [[WellIntentionedExtremist kind of]] but he's [[{{Jerkass}} kind of a jerk]] and his actions tend to cause people to make {{Face Heel Turn}}s. He's responsible for the StartOfDarkness of [[spoiler:Nagato/Pain and Kabuto]], worked closely with [[spoiler:Orochimaru]], and is one of the three major contributors to the tragedy of [[spoiler:Sasuke and the Uchiha clan massacre.]]
** The biggest example might be Tobirama Senju, [[spoiler:the ''Second Hokage''. His bigotry towards the Uchiha clan set a lot of the plot in motion, and he created Edo Tensei.]]
** His brother Hashirama isn't much better, as [[spoiler:he prevented Tobirama from killing Madara Uchiha before the Leaf Village was even founded.]]
** This trope is PlayedForLaughs in ''Manga/RockLeesSpringtimeOfYouth''. Whenever Hinata appears, expect someone to get hurt. Most of the time it's Naruto getting the receiving end of Neji's 8 Trigrams 64 Palms.
* Pretty much all the problems in ''Manga/{{Ojojojo}}'' can be traced back to when Mr Jigokumeguri started prepping his eldest daughter Haru to be heir to the family company when she was only a child. Because of that Haru ended up being shunned by her peers out of jealousy and adopted a RichBitch persona to cope (which, in turn, made her a social outcast for the next ''decade''). Meanwhile, her studying meant she could no longer spend any time with her younger sister Aki, who asked their father to let her compete for the position of heiress in hopes of spending time with Haru again. Aki ended up undergoing MotiveDecay and became a BitchInSheepsClothing.
* In an early ''Anime/{{Pokemon}}'' episode, Ash is right on the verge of capturing a Weedle, when he is rudely interrupted by a samurai, who challenges him to a Pokémon match. During said match, which is a MirrorMatch between their two [[StoneWall Metapod taking Harden commands]], the Weedle manages to escape back into its tree and alert the Beedrill, who capture Ash's Metapod. In one of the series' earliest {{Broken Aesop}}s, Ash is forced to learn a lesson about not making excuses about not finishing what he started, even though it was the fault of the samurai, [[NeverMyFault who berates him for all of this]], that Ash wasn't able to finish in the first place, all because he didn't have the courtesy to wait until Ash was done. Even after all is said and done, and Ash rescues Metapod, he's still short one Weedle, which would eventually evolve into a Beedrill.
* Hitomi Shizuki of ''Anime/PuellaMagiMadokaMagica''. There's this friend of hers, Sayaka, who likes Kyousuke, who lost the use of his arm in an accident. Hitomi also loves Kyousuke and decides to confess to him, but not before offering Sayaka the first shot since she believes it's the fair thing to do [[LockedOutofTheLoop and has NO idea that Sayaka REALLY can't confess]]. [[spoiler:Sayaka doesn't act on Hitomi's offer, her depression only worsens when she sees Hitomi confess to Kyousuke, and because of the nature of her DealWithTheDevil she [[AndThenJohnWasAZombie becomes what she fights]]. Kyouko self-destructs to MercyKill Sayaka]]. In short: Because of one mis-timed confession, two girls died.
** Some consider Madoka to be one. [[spoiler:Had she not tossed away Sayaka's Soul Gem, she wouldn't pass out/go all corpse-like and Kyubey wouldn't have spilled the beans, thus giving Sayaka that state of mind that she's no longer human.]] Although to be fair, her mother Junko also falls into this line for giving her that idea, although Madoka was not only ignorant of [[spoiler:what happens when a magical girl is separated from her Soul Gem]], but in addition to not mentioning that, gave her mother a vague description of what Sayaka was going through. As such, it becomes nearly impossible for Junko to give any good advice on that subject.
*** Kyouko is also to blame. [[spoiler:Had ''she'' not challenged Sayaka to fight, the already emotionally-unstable Madoka wouldn't had flipped her shit and tossed the Soul Gem to stop the eventual fight]].
** Madoka gets another one too: [[spoiler:Because she brought a mousy little introvert into their fold who took a great liking to Madoka, said introvert, Homura Akemi, became a ShellShockedVeteran. Moreover, in almost all of the timelines poor Madoka either dies or becomes the most powerful witch ever, due to Homura using her powers making Madoka more and more powerful as both a magical girl and a witch.]] It should be noted, however, that this is also what ends up [[spoiler:ending the very concept of Witches in the universe altogether.]]
*** Extrapolating on the above, the Drama CD reveals ''yet another one'': [[spoiler:the original Madoka's wish was to save a cat who was about to get hit by a car. Said cat, Amy, would eventually cause Homura and Madoka to make a bond, which would then result in Homura contracting, which would result in all the timeloops, etc. etc.]]
** Homura becomes one as well in ''The Rebellion Story''. [[spoiler:In the ending, she tells Kyubey of the Witch system, which because of what happened above is now just an unheard of thing for him. Bad idea, as he rigs the system to place Homura in a false world so that he could steal Madoka when she comes to save Homura just so he can use the Witch system again. ''Very'' bad idea for him though, as Homura takes matters into her own hands and ''she'' kidnaps Madoka, becoming the new Goddess. In a way, this trope zig-zagged, as Homura's mistake actually ''benefited'' her in the end... though it had to take someone else's mistake.]]
* ''Manga/{{Bleach}}'': Uryuu instigates a Hollow-hunting contest with Ichigo by using Hollow bait, inflicting on the town a massive onslaught of Hollow attacks that attract a Menos Grande. Uryuu is shocked because the bait is too weak to do this, and Soul Society is alerted to the AWOL Rukia's location, kick-starting the Soul Society Arc. The situation was in fact manipulated by Aizen to further his plans by having Rukia captured and sentenced to execution.
* In ''Manga/{{Bakuman}}'':
** One factor that contributed to Detective Trap losing popularity [[spoiler:and being canceled]] is two other similar manga- Phantom Thief Cheater and Detective Gosuke Akechi- both of which were submitted while Mashiro was in the hospital and on hiatus, and debuted after Mashiro's release.
** Near the end of the series, Mashiro mentions his relationship with Azuki around one of his assistant Kato's friends, who posts about it on her blog. As a result, [[spoiler:an in-universe InternetBackdraft [[YokoOhNo against poor Azuki]] ensues, and Azuki's bosses urge her to deny her relationship with Mashiro. She refuses, and ultimately has to outperform '''all''' other contenders to get the lead role in Mashiro's anime]].
* ''Anime/NeonGenesisEvangelion''. The pilots of Evangelion Transport Neopan 400, the American Weather Bureau and the technician at Airbase Ekta 64 are never named, are never spoken of again, but ALL are responsible for the entire [[KnightOfCerebus Bardiel Incident]] and CerebusSyndrome the show developed towards the later half. Long story short: not going around the suspicious-looking cloud equals TheEndOfTheWorldAsWeKnowIt.
* [[spoiler:Takehiko Henmi]] from ''Manga/OniisamaE''. [[spoiler:Six years before the story started, he visited his best friend Takeshi Ichinomiya's house and befriended his little sister Fukiko, who unbeknownst to Takehiko got a huge PrecociousCrush on him. She made him promise that he'd attend her birthday party and hear her play the violin, but he couldn't get to the Ichinomiya mansion in time and [[HeroicBSOD Fukiko was completely crushed]], becoming a {{Yandere}} over him.]]
* In Creator/RiyokoIkeda's other manga, ''Manga/{{Claudine}}'', there's [[spoiler: Claudine's best friend Rosemarie.]] Depressed because [[spoiler:Claudine doesn't return her feelings ''and'' she has found out that Claudine's crush Cecilia is actually [[YourCheatingHeart the lover of Claudine's *father* Auguste]] ]], she mentions this very complicated deal to [[spoiler: her teacher Louis, who is also Cecilia's younger brother.]] Little did she know that [[spoiler:Louis ''also'' had been Auguste's lover in the past... and that he would go {{Yandere}} on Auguste and Cecilia.]] The result isn't pretty: [[spoiler: Auguste and Cecilia die, the maddened Louis disappears, the Montesse family is devastated, and Rosemarie herself [[TwoFaced gets half her face horribly burned]].]]
* [[spoiler:Satoshi Oginome]] from ''Anime/MawaruPenguindrum''. [[spoiler:Had his estranged daughter Ringo not seen him with his girlfriend and her daughter, she would've likely not sped up her "Project M" to bring her family back together via the AttemptedRape of her crush, with all that happened later.]]
* Inverted with Isumi in ''Manga/HikaruNoGo''. If he hadn't insisted on playing Hikaru, [[spoiler:Hikaru would never have discovered that Sai is still present in his Go, would not have started playing again, would not have become the "second genius" and, therefore, [[UnintentionalBackupPlan would have caused the thousand-year plan of the god of Go to fail]]. At least, unless the whole chain of events [[GambitRoulette was just another part of the plan]].]]
* In ''Anime/DigimonSavers'' pretty much every bad thing can be blamed on one villain, the FinalBoss is just reacting to events. Drasil is such a self righteous blowhard that many people hated it just as much as the guy responsible for everything though, especially since much drama could have been avoided if Drasil had bothered to [[OrcusOnHisThrone get off its throne]] years ago.
* ''Anime/DigimonAdventure02'' has [[spoiler: Cody/Iori's grandfather, Chikara Hida. His son, Iori's dad Hiroki, was the only friend that eventual BigBad Yukio Oikawa had during his childhood; Chikara realized that this could become a very codependent relationship and forcibly separated them, which caused Oikawa to become an isolated and depressed man in his later years, obsessed with fulfilling the dream they had as children. This made him an easy prey for Myotismon's corruption, and drove him to orchestrate the events of the whole season. In the final episodes, Chikara realized his mistake and actually confronted Oikawa himself, even apologizing to him for his part, but it was too late by then.]]
* In ''Anime/SailorMoon'': Sailors Uranus and Neptune believe that victory cannot be attained without some [[MartyrWithoutACause horrible angsty sacrifice that only they have the moral strength to make]]. So basically, they make such choices that would make things worse at the end of the run. What they did in the GrandFinale is a major example in their habit to make bad decisions: [[spoiler:in a desperate gambit to reach for Galaxia themselves and keep their beloved Moon from dying, they pull a FakeDefector act that includes [[KillTheCutie killing Pluto and Saturn]] (depriving Moon of two valuable allies ''right after the death of Princess Kakyuu and the {{Heroic Sacrifice}}s of the Inners''), attacking Moon herself and her remaining allies the Starlights (so she wouldn't suspect them, but also [[CurbStompBattle weakening her physically]] [[BreakTheCutie and devastating her emotionally]]) and ultimately attack Galaxia on their own using powers she gave them after they faked choosing to serve her. But they didn't count on [[NoSell Galaxia being immune to the attack]] and they end up dying in front of Moon, Chibi-Chibi Moon and the Starlights [[SenselessSacrifice without accomplishing anything in the end]].]]
* ''Manga/MedakaBox'': Onigase, and by extension, the Public Morals Committee. Their antagonism towards the Student Council ends up getting Medaka and the other members dragged into the Flask Plan. In addition, Medaka's defeat of Unzen makes her an ideal candidate for the project and thus a target.
* In ''Anime/MagicalGirlLyricalNanohaAs'', Suzuka serves as one. She, not knowing about the Wolkenritter’s true nature or activities despite having met them as well as Hayate, plans to pay Hayate a surprise visit along with Arisa, Nanoha and Fate on Christmas Eve in Hayate’s. Nanoha and Fate, seeing the Wolkenritter with Hayate, then realize that Hayate is the true master of the Book of Darkness that they are searching for, and are forced into a confrontation with the Wolkenritter, who wish to prevent Hayate from being exposed. [[FromBadToWorse Things quickly get worse from there.]]
* In ''Anime/MaiOtome Sifr'', a cat wandering out on the hotel balcony leads to Sifr trying to retrieve it, and falling and having to be rescued by Lena, who berates her for going outside and risking being discovered. It's revealed that one of the poolgoers was an undercover Schwarz agent, and that night, a large Schwarz force attacks, succeeding in kidnapping Sifr with help from M9.
* [[spoiler:Michiru Saotome]] from ''Manga/GetterRobo Armaggedon''. [[spoiler:She's [[FateWorseThanDeath infected with]] TheVirus, and chooses to commit suicide via [[BetterToDieThanBeKilled screwing up with a test flight]] rather than suffer a really painful death]]. While such a situation is really bad and one can sorta understand the logic behind such a drastic decision, there are even worse things about it: [[spoiler:her father, Dr. Saotome, mistakenly believed that the Getter pilots were to blame, leading to him becoming a MadScientist... which is followed by his murder, Ryoma's imprisonment, Saotome being BackFromTheDead and completely AxCrazy, '''and''' the invasion.]] (Not to mention [[spoiler:her [[RaisedAsTheOppositeGender little sister Genki]], [[HarmfulToMinors who witnessed Michiru's death in first row]], is [[BreakThecutie horribly traumatised]] to the point of becoming a CreepyChild]]). On top of that, said incident drove a rather large wedge between Getter pilots Ryoma and Hayato, to the point where each of them outright wants to murder the other at the start of the story; it isn't until '''several''' years later, when they learn the truth about [[spoiler:Michiru's death]] that they start really working together the way they did back as teammates.
* In ''Manga/FullmetalAlchemist'', Heinkel manages to corner Pride, only for some residents of the nearby slums to come by with sources of light. This enables Pride to set fire to the brush nearby, regain use of his shadow powers and severely wound Heinkel.
** Earlier on, Edward and a nameless character share responsibility for [[spoiler:Winry getting a HeroicBSOD and trying to kill Scar, potentially putting her own life in danger]]. The former mentions [[spoiler:Scar killing Winry's parents]] while unbeknownst to him, [[spoiler:Winry]] is in earshot, and the latter, an MP knocked out by Scar, accidentally leaves behind a pistol for [[spoiler:Winry]] to pick up.
* [[spoiler:Kalos Eidos]] from ''Anime/KaleidoStar'' believes himself to be one of these. [[spoiler:Ten years ago, he asked a famous acrobat and close friend of his named Aaron if he truly was up to performing the very dangerous Fantastic Maneouver, that had caused more than one death... and afterwards, Aaron failed to do it and died]]. This is the reason why, a decade later, [[spoiler:Aaron's son and former Kaleido Stage Ace Yuri is pissed off at Kalos enough to try buying out the Stage as revenge... and Kalos does nothing to stop him [[TheAtoner since he thinks it's his punishment]] [[MyGreatestFailure for letting Aaron die]].]]
* In ''Anime/MaiHime'', while Yuuichi's desire to help Mai is commendable, several of his actions end up making things worse for her.
** Yuuichi uttering Mai's name when he catches her with Reito ''when Shiho is with him as well'' results not only in Reito being upset at him but in Mai attracting Shiho's jealousy, since Shiho accuses Mai of lying to her about Mai's own desire to [[ShipperOnDeck root for her love for Yuuichi]].
** Yuuichi tells an ill Shiho that [[spoiler:Nao is attacking Takumi]]. As a result, [[spoiler:the [[{{Yandere}} increasingly unstable Shiho]] slips out of the hospital and destroys Akira's Child with her Hime powers, killing Takumi out of spite for Mai]].
** When Yuuichi goes to [[spoiler:save Mai from Yukariko]], he also ends up missing an appointment to meet Shiho in the park, [[spoiler:causing the despairing Shiho (who, for worse, is now fully under the influence of [[ManipulativeBastard Nagi]]) to fully lose it and directly attack Mai, leading to a battle that ends in ''Yuuichi's death'']].
** In Mai's past, an unnamed girl called her over to play while she was watching Takumi. While she was gone, Takumi went into the river and almost drowned, forcing his and Mai's mother to save him, leading to her death, Takumi's weakened heart and Mai dedicating herself to taking care of Takumi in order to atone for her mistake.
* In the ''Manga/SoulEater'' manga, most of the arc invading Arachne's castle started up when [[spoiler:Kim]] was suspected of [[spoiler:being a witch]] and a random, nameless DWMA agent decided to immediately arrest her by force instead of talking to her first like everyone else was planning. A bigger example would be [[spoiler:Death attempting to 'free' himself from fear by creating [[MadGod Asura]]. Creating an Anthropomorphic Personification of ''unrelenting terror'' did not go well, as Death apparently made an entity that was a) equal to him in {{p|hysicalGod}}ower and b) unlike his [[EldritchAbomination fellows]] eventually cannot be reasoned with.]]
* In ''Anime/GirlsUndPanzer'', when Hana introduces her friends to her mother, Yukari mentions that she's in a different class from Hana, but they're doing tankery together. Yukari doesn't know that Hana's mother doesn't know [[FantasyForbiddingMother or approve]] of Hana doing so, and Hana's mother ends up fainting on the spot and later (temporarily) disowning her. Yukari apologizes to Hana for her role in this, but Hana doesn't hold it against her, feeling as though it's her own fault for not telling her mother.
** Koume Akeboshi, [[spoiler:whose tank plunged into a river during the previous tournament finals, resulting in Miho abandoning the flag tank to save it, and causing Black Forest to be defeated when their enemies fire on the flag tank]], blames herself for Miho deciding to leave Black Forest, seeing herself as causing Miho trouble.
* In ''Manga/JojosBizarreAdventure'', George Joestar I's well-intentioned adoption of Dio Brando leads to his death, his son's death, his grandson's death, his great-great-great-grandson's death, his great-great-great-great-granddaughter's death, the deaths of countless others, and nearly causes the end of the ''entire universe''.
** Dio's father Dario also counts as one. If only he wasn't such a petty thief and a gigantic {{Jerkass}} of an [[AbusiveParents Abusive Father]], not to mention take care of his wife better, Dio could have tempered the evil within him that he carried since his birth, since it's known that [[EvenBadMenLoveTheirMamas he loves his mother]], instead of causing... well, see above.
** On a less cosmic scale, a trio of school girls are the reason why a serial killer was able to get away for so long. To explain: [[spoiler:these girls encountered a kid who was motally wounded by said killer. Rather than go get help or call a teacher, they instead leave him. This in turn causes him to be finished off by the killer, and thus, allows him to get away scot free for at least a few more arcs]].
* In ''VideoGame/TheKingOfFighters: KYO'' manga, there are three of these: Iori Yagami, Sanae and Takaya Maeta. Iori challenged Kyo to a ''very'' violent fight outside the school grounds, which prompted Kyo's girlfriend Yuki as well as Athena Asamiya to defend him (and in Yuki's case, [[GoThroughMe at great risk to herself]] since she's '''not''' an ActionGirl). The day after this Sanae introduced Maeta to Yuki, trying to rope her into having a date with him despite Yuki's own reluctance. [[spoiler:Unbeknownst to all of them, the botched fight with Iori had triggered Kyo's hidden insecurities -- and it was soon followed by a challenge from Maeta ''and'' Daimon to Kyo, who lost '''badly'''. All of these factors piled up on Kyo's own psyche: soon he was so troubled that he got BroughtDownToNormal, then suffered a '''severe''' HeroicBSOD. If not for Kyo's father Saisyu going WarriorTherapist on him, Kyo would have ended up ''as a BrainwashedAndCrazy BloodKnight completely controlled by {{Orochi}}''.]]
* In ''Manga/{{Lady}}'', a group of English kids are seen playing with a ball in the streets of London during one of the first scenes of the manga... Had one of the kids not gone for their missing ball in the worst moment possible, the guy driving the car that Lynn and her mother Misuzu were in wouldn't have tried to dodge her too fast and wouldn't have crashed, which in turn ''[[DownerBeginning would have not costed Misuzu her life and would've brought much less trauma to Lynn]]''.
* ''Manga/RosarioToVampire [=Capu2=]'': Kokoa is responsible for not one, but two disasters during the anime:
** First, she badmouths curry in front of Apsara, who snaps and force-feeds her special curry to turn her into a "curry zombie" before doing the same to the rest of the school.
** Then, a few episodes later, she steals Lilith's Mirror from the academy with the intent to use it to get Inner Moka back, but ends up mixing up packages with a visiting Kyouko, who inadvertently uses it to cause all of the academy's students to revert to their monster forms and go on a rampage, which almost breaks down the barrier maintaining TheMasquerade and forces Moka to give up her rosary to fix it.
* ''Manga/RoseOfVersailles'': The Duke of Orleans secretly works to discredit Louis XVI and Marie Antoinette and aids individuals unhappy with the monarchy, hoping to use popular support to become King himself. However, the discontent he helps feed leads to a full-scale revolution culminating in the destruction of the ''ancien regime'' and the formation of the French Republic.
* ''Manga/YourLieInApril'': Hiroko was the one who convinced Saki to make Kousei into a pianist after seeing his great talent. After Saki became sick, she became more demanding and abusive towards Kousei, eventually damaging their relationship beyond repair and leaving Kousei with deep emotional scars. Hiroko always blamed herself for Kousei's problems because of it.
* In the [[AllThereInTheManual notes]] left by the late ''Anime/TrinityBlood'' author, Sunao Yoshida, Seth Nightroad's actions led to two damning consequences. First, it's revealed that she injected the Crusnik nanomachines on her oldest brother, Cain, to save him after he got into an fatal accident during the Red Mars colonization project. Unfornately, it made Cain insane and drove him to destroy the world. Though Cain secretly hates humanity, the nanomachines that Seth injected just gave him the power to do so which resulted to killing Lilith Sahl and taking her nanomachines. It wasn't clear if Seth knew what she had done but she realized that Cain is no longer the brother that she and Abel loved. Second, according to the notes, [[spoiler:she activated the satellite cannon of the Ark hidden in the imperial palace to destroy nuclear military base of the Vatican to prevent Francesco from using it when the Terran-Methulesah war broke out again and this gave Cain the chance to use the Ark and have Dietrich fire the satellite cannon on Rome, resulting to the Vatican's destruction. This bites back her in the dust ''badly'' when she stopped Cain from using the Ark which got her killed, her nanomachines stolen by him and the Empire going for an all-out counterattack on the humans by conquering their territories]].
* Clow Reed is guilty for all the things that had happened in ''Manga/TsubasaReservoirChronicle''. His unconscious desire [[spoiler:to resurrect his beloved Yuuko Ichihara]] gave birth to Fei Wong Reed, who tries fulfilling it... at the cost of the lives of millions of people across multiple dimensions and ruining the lives of the four main characters.
* ''Anime/BloodPlus'': Though Saya Otonashi is the one who released Diva to the world, the first Joel is responsible for Diva's state of mind given that he secluded her in a tower with no contact from anyone except Amshel and treated her as a lab rat while he pampered Saya like his own daughter.
* ''LightNovel/UndefeatedBahamutChronicle'': [[spoiler:Celestia Ralgris revealed the Empire's corruption to Lux's grandfather Wade Roadbelt, who confronted the emperor about it. In response, the emperor imprisons Wade and leaves him to die and banishes Lux's side of the family from the court, creating a chain of events that lead to the death of his mother, the fall of Arcadian Empire, and him being reduced to a local chore boy. Unlike most examples of this trope, Celestia is fully aware of what her actions have caused and has felt guilt over it for the next five years.]]
* ''Manga/FairyTail'':
** In Zero, Yuriy Dreyar, Makarov's father and one of the founders of Fairy Tail, serves as this. When trying to take the [[ArtifactOfDoom Sirius Jade]] for himself, he ends up transformed into a monster under its control, and forces Mavis to use Fairy Law on it to save him, resulting in her being unable to age. It later turns out that the consequences are even worse than they thought, since [[spoiler:Mavis actually has the same curse as [[BigBad Zeref]], one that kills anyone near her so long as she values life, and this results in Yuriy's wife dying, forcing Mavis to flee and meet up with Zeref. Mavis falls in love with him, which leads to his curse killing her, and many other developments that essentially lead to the plot of the series taking place]].
** In the main series, Porlyuscia misdiagnoses [[spoiler:Natsu]], saying that he [[spoiler:has an anti-ethernano tumor]] when in reality, it's something far worse. Brandish, a villain who's torn between her loyalty to Albareth and the heroes who showed her kindness, [[PetTheDog apparently cures]] [[spoiler:Natsu by shrinking the tumor]], then reverses the process to "prove" to her watching comrades that she's still on their side. Unfortunately, Porlyuscia realizes her mistake too late, so her (and in turn, Brandish's) ignorance about Natsu's condition [[spoiler:leads to Natsu's E.N.D. side awakening, and later, his Demon Seed trying to merge with his Dragon Seed, a process that if completed, will kill Natsu]].
* In ''Anime/GuiltyCrown'', Shu Ouma rejecting his sister Mana's advances causes the Lost Christmas event, dooming Japan in the process.
* In ''Anime/HighSchoolDxD'', Azazel dispatches Raynare to keep an eye on Issei Hyoudou's Sacred Gear, but he ends up being indirectly [[NiceJobBreakingItHero responsible]] for Raynare [[DeathByOriginStory killing Issei]] at the beginning of the series.
* 'LightNovel/AccelWorld'',
** In the anime, Chiyu, reading a news report about Kuroyukihime being hospitalized, while unaware that her Neurolinker's been infected with a backdoor program, inadvertently gives Taku/Cyan Pile the information of where to find her. Since Kuroyukihime is unconscious, still connected to the net and almost out of points, Taku would essentially get a win by default if he challenged her, had Haru not intervened.
** Cherry Rook and Scarlet Rain(aka Yuniko "Niko" Kozuki) are two orphans growing up in the same facility, and Cherry introduces Niko to Brain Burst, thereby becoming her "parent," [[ObsoleteMentor but is dismayed to find that Niko quickly surpasses him]]. The final straw is when some of Cherry's real life relatives offer to adopt him and take him away from the facility, which means that Brain Burst will be the only connection he and Niiko have left, and makes him so desperate that he accepts the Armor of Catastrophe and becomes Chrome Disaster. The heroes defeat him and he manages to come to his senses in the real world, promising to stay in touch with Niko, but [[spoiler:during the fight, Haruyuki gets infected with the Disaster, which causes problems several volumes later]].

[[folder:Comic Books]]
* In an issue of one of the ''ComicBook/UltimateMarvel'' comics, Captain America told Spider-Man that he was not ready to be a hero and that he did not deserve to wear the costume. [[spoiler:Spidey's {{determinat|or}}ion to prove Cap wrong is what leads to his untimely death.]]
* In Volume 5 of ''ComicBook/ScottPilgrim'', Stephen Stills tells Knives that before Scott broke up with her, he had already started dating Ramona. Knives then tells Ramona, leading her to [[spoiler:break up with Scott]].
* Inverted in the ''Franchise/{{Tintin}}'' story ''Recap/TintinTheSecretOfTheUnicorn'' with the pickpocket who had been stealing everyone's wallets. [[spoiler:He ended up stealing the Bird brothers' wallets which contained their parchments, this lead them to think that Tintin stole their wallets. They ended up kidnapping Tintin, and after a long chain of events, they got captured. Tintin got the last two parchments from the pickpocket and ended up finding Red Rackam's treasure.]]
* In the ''ComicBook/ArchieComicsSonicTheHedgehog'' book this applies to Sonic, Sally, Knuckles, and Tails's respective families. Issue 50 revealed that Sonic's dad and uncle found Robotnik and brought him to King Max, who made his infamous decision to make him the new Warlord. During this time up to when they were captured, Knuckles' father and ancestors were aware of Robotnik, but devoted none of their considerable resources to resolve those problems, despite Robotnik once trying to weaponize the Floating Island in the Sonic and Knuckles tine-in comic, trying to drive the island into the sea in the Death Egg saga and Knuckles spin off title revealing his family was still living on the island and would've been aware of this; Locke even commented on the Ultimate Annihilator in the spin off title. And almost immediately after they returned, Tails's parents caused a political reformation that may well have resulted in, in addition to [[spoiler:King Naugus]], the disaster Silver's trying to prevent.
* ComicBook/XMen villain [[MasterOfIllusion Mastermind]] when he turned Phoenix into Dark Phoenix. He thought he was merely brainwashing Comicbook/JeanGrey and capturing the X-Men as part of his bid to join the Hellfire Club's Inner Circle. Neither he nor the rest of the club realized they were messing with a cosmic entity and ended up putting the entire universe at risk.
* When SelfDemonstrating/{{Magneto}} first manifested his powers, an angry mob burned his house down and prevented him from saving his daughter Anya from a fire, causing him to use his powers to murder them all and permanently estranging his wife Magda. It's the first time Magneto takes a life, but not the last...
** While pursuing Magneto-worshipping mutants to Asteroid M, a {{SHIELD}} agent shoots one of them, who [[spoiler: nearly]] dies in Magneto's arms. This triggers another FaceHeelTurn from the formerly-retired Master of Magnetism.
*** At the same time Magneto found out Moira [=MacTaggert=] had been tinkering with his genetic code, apparently attempting to force him to reform. To call him "displeased" would be an understatement.
** In response to Magneto's later return, the governments of Earth surround the planet in a satellite shield that will prevent Magneto from returning to Earth. In response Magneto [=EMPs=] the ''entire planet'', causing catastrophic casualties. In response to ''that'' the X-Men attack Asteroid M, ultimately leading to Charles Xavier mind-wiping Magneto and creating Comicbook/{{Onslaught}}, who nearly destroys the planet and does [[spoiler: temporarily]] kill of most of Marvel's superheroes. All because the Earth governments launched a pre-emptive defense against a man who was, at the time, content with splendid isolation.
** Magneto is later (publication-wise) targeted by Legion, Xavier's son, who believes killing Magneto before he can get started will bring about the utopia his father always wanted. Legion screws up and kills Xavier instead, resulting in the ''ComicBook/AgeOfApocalypse''.
** Magneto finally catches the short end of the stick when Cassandra Nova convinces Donald Trask III, Bolivar Trask's last living relative, to reactivate a South American Sentinel program and attack Genosha. Trask is a dentist who seems too stupid to understand the full implications of what he's doing, namely murdering 16 ''million'' mutants.
* Having used a XanatosSpeedChess style plan to save the world a few times, Kid Loki find out, to his horror, that pretty much everything he's done during ''ComicBook/JourneyIntoMystery'' has come back to bite him in the ass all at once -- the main villain of the Everything Burns crossover is [[spoiler:Surtur]], who was originally released by Loki, he's aided by [[spoiler:The Manchester Gods]], who gained their power with Loki's help, and [[spoiler:Surtur's]] herald is [[spoiler:the alternate version of Leah that Loki had written into the Serpent's backstory]]. Right after he clears all of that up, he discovers that [[spoiler:Mephisto, still angry at Loki for releasing the Disir from their curse, has found out about the Fear Crown that he'd created and is going to use it to create a literal hell on earth]]. Unlike a lot of examples here, because he's the protagonist, it comes across as being more tragic than annoying -- no matter what he does, something's going to come along and ruin his happiness and success.
* ''Comicbook/TheTransformers'':
** In the original comic, Octopunch tried to shoot Grimlock during a battle in Cybertron's core. However, the blast harmlessly bounced off the Dinobot leader and instead struck Primus himself, causing him to let out a scream that allowed Unicron to find his way back to Cybertron.
** In the IDW comics, Whirl is a minor example - while the Senate had pressed him into service, Megatron points to him as the one who taught him to rebel against the Senate with violence, thus starting the Great War.
-->'''Whirl:''' Did I ever tell you about how I started '''our''' war? You'll laugh your head off.
* In ''FF #5'', [[ComicBook/FantasticFour Reed and Susan's]] children Franklin and Valeria viewed a set of [[VideoWill holographic wills]] their family left them. Ben confesses his deepest darkest secret in his: [[spoiler:back in college he was pissed off by a certain {{Jerkass}} who kept mocking his best friend Reed. So one day Ben snuck into the guy's room and messed around with one of his experiments...]] This is a doubly appropriate example given the moniker the guy would start using after that day.
* ''StarWars ComicBook/{{Legacy}}'': Obi-Wan once cut off a tusken raider's arm to protect some moisture farmers. That tusken raider was cast out by his tribe, and went on to become a new Sith Emperor who will create the One Sith, and start a new war that was will result in the deaths of billions of life forms.
* In ''ComicBook/TalesOfTheJedi'' a pair of hyperspace explorers Gav and Jori Daragon stumble upon the homeworld of the Sith race. The Sith lord Naga Sadow engineered a scheme where he frees the explorers, and lies to his people that the Republic will invade their empire, thus starting the Great Hyperspace War.
* ''First X-Men'' has Victor Creed's then girlfriend, Holo die, and he blames Wolverine for convincing her to stay and fight with him. But that shouldn't be a big deal for Victor, who is over one hundred years old, and they only had a short relationship, right? Well, when she was mortally wounded, she used her powers to show Victor an illusion of the two having a family and living a long, fulfilled life, and he thought that was what was happening and experienced it first-hand, and she told him that ''this'' is what he should remember... before cutting the illusion and revealing that she was actually still mortally wounded. She tells him that it "doesn't have to mean anything less". Well, he took this to heart, and determined that it logically meant that Logan had taken it all ''away'', and would spend the rest of his life ensuring that Logan would never find any''thing'' or any''one'' worth living for ever again. So it's less "you got my short-term girlfriend killed" and more "you took away my happy ending". On that day, Holo's nice little parting gift and last words created an archnemesis for Wolverine that would go on to menace him and everyone around him for the rest of his life. And they're both immortal.
* In ''ComicBook/TheMultiversity'', Ultra Comics is [[spoiler:exploited by the Gentry as a means to infiltrate the multiverse]]. While he manages to [[spoiler:seal Earth-33 off from them]], he's ultimately unsuccessful in [[spoiler:defeating the villains]].
* The race known as the [[ComicBook/GreenLantern Guardians of the Universe]] practically has this as its ''[[PlanetOfHats hat]]''.
** One member of their race, attempting to settle the Origin Question (basically, why is there a universe and why is there life in it and specifically why are there Oans/Malthusians in it), [[ComicBook/CrisisOnInfiniteEarths introduced Evil (or at least Entropy) into the universe]].
** To combat evil, they formed a corps of robotic police called the Manhunters. That didn't work out so well.
** To combat evil ''and'' the Manhunters, they decided that another Corps was the way to go, this time the Green Lantern Corps. Noble in principle, but they also decided to [[SealedEvilInACan seal the Fear Entity inside the artifact giving the Green Lanterns their power]]. That [[ComicBook/ZeroHour didn't work out so well either]].
** Really, anytime something in the DC Universe is going very badly on a cosmic scale, the Justice League could save themselves some detective work by starting with the assumption that it's at least related to something that either Darkseid did on purpose or the Guardians did by accident.
* ''Comicbook/CivilWar'': The entire mess started no thanks to the Comicbook/NewWarriors who ambushed a bunch of fugitive supervillains ''in the middle of suburbs'' in Stamford while filming for a RealityTV show which provoked Nitro to blow up, destroying the entire city, killing the entire population including them. As a result, the hate on superhumans increased more which convinced the Congress to pass the [[SuperRegistrationAct Superhuman Registration Act]] and it further divided the superhero community, culminating to Hydra's assassination on Captain America and the rise of Comicbook/NormanOsborn's Comicbook/DarkReign.
* Sabrina accidentally causes a ZombieApocalypse in ''ComicBook/AfterlifeWithArchie'' when she tries to revive Jughead's dog, Hot-Dog.
* In ''Franchise/TheFlash'', the Allens come to a doctor to deliver their twins, the same time as the Thawnes are expecting a delivery as well. The Thawne child died in childbirth, and, out of guilt, the doctor gave one of the Allen twins to the Thawnes while fabricating a lie to his real parents that he died. Malcolm "Thawne" grows up in a dysfunctional, criminal family, and when he learns of his true parentage, comes to resent his twin brother Barry as a result. While Barry successfully heads a mostly-familial legacy of superheroes, Malcolm would become the ancestor to multiple supervillains (the second Reverse Flash, Captain Boomerang II, Inertia, not to mention multiple other descendants that bear Malcolm's "Cobalt Blue" villain moniker), creating one of the largest FeudingFamilies in the DCU.

[[folder:Fan Works]]
* In ''Fanfic/MarieDSuesseAndTheMysteryNewPirateAge'', [[spoiler:Eustass Kid wonders aloud in front of Madelyn what would happen if the Straw Hats were delayed, making it possible for the Kid and Heart Pirates to compete for One Piece.]] The "unwitting" part comes from the fact that he doesn't realize [[spoiler:Madelyn, with her powers]] could make this happen, or that she would want to. [[spoiler:Madelyn then concludes that Law has lost his spirit for pursuing One Piece because he thinks Luffy will win, and then wishes for him to get captured to force his crew to go after him; this ends with Luffy's execution and the deaths of all the other Straw Hat pirates, among other events.]]
* While most ''Fanfic/ImperfectMetamorphosis'' readers quite rightly blame Team 9 for nearly everything, they couldn't have even stolen [[spoiler:Rin Satuski's]] [[SealedEvilInACan can]] in the first place if Marisa hadn't stolen it from Patchouli. Marisa's StickyFingers are the only reason anything in the story happened.
* Back in the original series, Yamada Tatsumori/Aries Zodiarts was the one who instigated the DealWithTheDevil with Ryusei so Ryusei could revive his friend. What happens in ''FanFic/HorseshoesAndHandGrenades''? The deal with Gentaro dead gave Ophiuchus a way to wreak his havoc on the world (and bring in other Serpents for the ride) and having nearly ''every'' named character from Fourze involved in multiple adventures to stop Gamou's advent of injecting former Switchers with Cosmic Energy, the origins as to why Ophiuchus is causing this madness and Ryusei being brainwashed and transformed into a cyborg. Didn't think this through, did you, Apostle of Sleep?
** Ryusei also should be blamed for killing Gentaro in the first place considering that Tachibana had stated that there was an alternate and ''safer'' way to bring Jiro back to life.
* In ''Fanfic/BoysUndSenshado'', two pop up in [[WhamEpisode Chapter 6, with consequences for Chapter 7]]. The gunner of the Semovente [[spoiler:shoots Miho by accident]]. In the ensuing chaos, Mako almost makes the mistake of [[spoiler:running over Miho]]. Miho, while [[DisappointedInYou disappointed in Mako]], refuses to punish her, which results in Miho's mother [[spoiler:disowning her]].
* Twilight Sparkle in ''Fanfic/DividedRainbow'', for causing the {{Swap|pedRoles}}.
* [[spoiler:TCB!Lyra Heartstrings]] is revealed to be this in ''Fanfic/TheConversionBureauTheOtherSideOfTheSpectrum''. [[ForWantOfANail It turns out]] that the reason why the MirrorUniverse Equestria turned into [[TheEmpire the Solar Empire]] and is carrying out its [[AssimilationPlot ponification crusade]] against humanity is all because [[spoiler:she went on a scuba diving trip with some friends where she happened upon the sunken ship of the KV-62 Archaeological Party coming from [[WesternAnimation/MyLittlePonyTVSpecials Dream Valley]]. Unfortunately, she also found the [[ArtifactofDoom Bag of Tirek]], which seeks to carry its maker's will out by enslaving every living being in existence and targeted humanity first [[DisproportionateRetribution out of revenge]] because Tirek himself had been by a human in the past]]. However, it's also heavily implied that she was just as much an UnwittingPawn too.
* ''FanFic/RosarioVampireBrightestDarkness'':
** The entire Ghoul!Tsukune subplot in Acts II and III occurred because Kokoa failed to perform a vampire blood transfusion to save his life at the end of Act I properly. Not only that, but the entire reason said blood transfusion was needed in the first place is because while sleeping in his room with him, Moka sucked his blood dry and nearly killed him in her sleep.
** As revealed in Act III chapter 15, while making Yukari a new wand, Apoch and Astreal misread the instructions to do so and make her the [[EvilWeapon wrong one]]. As a result, Yukari gets DrunkWithPower and tries to kill the gang in a fit of rage, causing Tsukune to break ''two'' more links on his [[RestrainingBolt Holy Lock]] in order to stop her and destroy the wand. All of that chaos happened simply because Apoch and Astreal misread an instruction booklet.
** It's also revealed over the course of Act III that Kenzo had had one of his men follow Dark the night he hid Felucia's [[SoulJar spirit artifact]] to ensure it was in a safe place. While he was well-intentioned at first, [[spoiler: Hokuto finds this out and sends Kuyou after Kenzo in order to discover its location. The end result: Kenzo ends up dead by Kuyou's hands, and Hokuto gets his hands on Felucia's spirit artifact and uses it to extort Felucia into being his minion]].
* From the later parts of ''Fanfic/Gensokyo20XX'', we have an age-regressed Reimu, who was conditioned not to sense danger. This is especially so in 20XXIV, when she crawls out of the house right into danger, which has Ran almost raped by another male kitsune. From 20XXV, we have the unknown and unnamed tenant who left rat poison where the aforementioned could get it and it leading to her suffering brain damage in the aftermath.
* In ''FanFic/TheVow'', while in a sad and angry stupor over [[spoiler:his wife's death]], [[{{Jerkass}} Lord Chang]] tells [[WesternAnimation/KungFuPanda2 Shen]] that he's only living in his parents' shadow and that history shall never remember him for his great achievements. Haunted by those words, Shen ends up accidentally inventing black powder, starting his canonical dark path.
* The timeline of ''Fanfic/TheDearSweetieBelleContinuity'' was triggered when [[spoiler:Nevermore]] saved a foal from a cart crash during a fixed point in time, which first caused [[spoiler:the foal's father Feather Duster not to get shocked out of his alcoholism]] and ultimately led to [[spoiler:the destruction of the universe via magical shockwave in an attempt to stop a war- at least before the [[TimePolice Guild of Time Defense]] swore to prevent it]].
* The Cell example in ''Anime/DragonBallZ'' is ramped up some more in ''WebVideo/DragonBallZAbridged'' - it turns out that Trunks had surpassed his father in sheer power and could have killed Cell at any time. However, he held back because he knew that if his father sensed it, it would break him. It's implied that Krillin sensed Trunks' greater power, causing him to destroy the remote.

[[folder:Films -- Animation]]
* P.T. Flea from ''WesternAnimation/ABugsLife'' got Flik and the circus bugs ostracized by the colony and then later in the film incinerated a fake bird, thinking it was the real deal. Earlier in the film he had also fired the circus bugs, leading to them meeting Flik and setting the plot in motion.
* Both Gringoire and Djali serve as this in the Burbank Films Australia [[WesternAnimation/TheHunchbackOfNotreDameBurbankAnimation adaptation]] of TheHunchbackOfNotreDame - firstly, Gringoire tells Frollo where Esmeralda is going, thus allowing the priest to find and stab Phoebus, then Djali performs a trick during Esmeralda's trial, thus "proving" the accusations of witchcraft. Luckily, disaster is averted when Quasimodo rescues Esmeralda.
* In ''WesternAnimation/TheIncredibles'', Buddy Pine is to blame for the FrivolousLawsuit, SuperRegistrationAct and everyone being forced into hiding. But in the end he makes the Supers re-emerge and being hold as heroes again, thanks to his failed scheme.
* Hot Rod was a borderline TheLoad during the fight between Optimus Prime and Megatron in ''TransformersTheMovie''. He promptly was hostage by Megatron, resulting in Optimus's death.
* In ''WesternAnimation/KungFuPanda'', Shifu's goose messenger to Tai Lung's prison gives him both the means to escape and the motivation to do so. Blame is also placed on the prison commander for dislodging the feather Tai Lung used to escape.
* ''Disney/WreckItRalph'': If Gene hadn't goaded Ralph into getting a medal, many, ''many'' problems could have been avoided. [[InvertedTrope On the other hand]], [[spoiler:no one would have discovered a dark secret about Sugar Rush either]].
* The whole main plot of ''Disney/{{Frozen}}'' is caused by Hans' horse. It knocked into Anna, [[CrashIntoHello prompting her and Hans' meeting]], which led to their engagement, which led to Elsa's bout of PowerIncontinence and her panicking, fleeing, and burying Arendelle in snow. [[spoiler:Of course, given what we learn of Hans later in the film, he may have arranged most of this; though he didn't know about [[PersonOfMassDestruction Elsa's powers]] [[PowerIncontinence before they were revealed]], [[LetNoCrisisGoToWaste he did his best to take advantage of the opportunities that arose]].]]
** Not helped by the fact that most of her emotional duress (as well as Anna's social awkwardness [[spoiler:that Hans exploits]]) were the result of her parents shutting them away from the world in an attempt to control her powers, when really they just hid them and never focused on helping her learn to control them.
* In ''WesternAnimation/{{Home}}'', [[spoiler:during an attempted peace conference with the Gorg, Captain Smek ran and grabbed a small rock on the way out, placing it on his "shusher wand." It is later revealed that the rock actually contains the next generation of Gorg, which is the true reason the Gorg has been chasing the Boov]].
* Nakoma in ''{{Disney/Pocahontas}}'' plays with this. She tells Kocoum about Pocahontas meeting John Smith precisely because she ''wants'' something to happen. But she was hoping Kocoum would bring Pocahontas home and stop her from fraternising with the settlers. She certainly didn't expect Kocoum to witness a kiss, try to kill John in a blind rage and get shot by Thomas - thus leading to the near genocide of both sides. While she [[EasilyForgiven never gets called on her actions]], she is clearly horrified by what has happened and does her best to make it up to her friend.
* In ''WesternAnimation/ThePowerpuffGirlsMovie'' the children who ask the girls to play tag with them on the first day. This leads to the girls getting carried away with their powers and causing ''massive'' amounts of destruction to the city. Thus Professor Utonium is held responsible and thrown in jail, allowing Mojo Jojo to convince the girls to side with him and nearly enslave the city.
* Andy's Mom in the 3 ''Franchise/ToyStory'' movies:
** In the first, her insistence that Andy can only bring one toy with him to Pizza Planet ends up causing Woody, knowing Andy will pick Buzz over him, to accidentally knock him out of a window, leading to both of them getting lost.
** In the second, her decision to sell Wheezy at the yard sale leads to Woody going out to the sale to save him, and Woody ends up getting stolen by Al.
** In the third, she accidentally brings the toys out to be thrown away, even though Andy intended to store them in the attic. The miscommunication causes them all, besides Woody, to donate themselves to Sunnyside.
* King Triton in ''Disney/TheLittleMermaid'' destroys Ariel's collection of human objects as a way of trying to teach her a lesson. Little did he know that Ursula was waiting for a moment where Ariel was vulnerable and prone to making rash decisions. Thus she's able to convince Ariel to make a deal with her - which is all part of her master plan to get control of the trident.
* Anger from ''WesternAnimation/InsideOut'' frequently makes Joy and Sadness's journey back harder by making Riley overreact in ways that bring down several of the Islands of Personality, which they're trying to cross to get home. [[spoiler: When he puts in the idea bulb to run away, not only does Honesty Island's resulting collapse bring down the Train of Thought, which Joy and Sadness were on at the time, but the idea also destabilizes Family Island before they can cross it, leaving them without any easy way home. As if that wasn't bad enough, when Anger finally sees Family Island crumbling and realizes it's a bad idea, he does so just in time for the console to lock out him, Disgust, and Fear from being able to stop Riley.]]

[[folder:Films -- Live-Action]]
* ''Franchise/StarWars'':
** In ''Film/ANewHope'', the Star Destroyer officer who orders his subordinate not to fire on the escape pod containing C-3PO and R2-D2, thus ensuring that Luke Skywalker gets Princess Leia's message and brings about the end of the Empire. If this nameless officer had not been so frugal with laser ammo, TheDarkSide would surely have triumphed.
** In ''Film/AttackOfTheClones'', the one thing that Jar Jar actually does in the movie, other than [[DemotedToExtra stand in the background]], is to make a motion in the Senate to grant Palpatine emergency powers. Yes, ''[[BigBad that]]'' [[MagnificentBastard Palpatine]]. Jar Jar was already so despised at this point that the reaction was mostly along the lines of "He was the cause of all the evil in the universe? ''I knew it!''"
** If Admiral Ozzel in ''Film/TheEmpireStrikesBack'' hadn't been so impetuous and exited hyperspace too close to Hoth, the Rebels wouldn't have had time to set up the shield generator and the Imperial fleet could have just bombed them form orbit. This leads to the trope namer for YouHaveFailedMe.
** Wicket in ''Film/ReturnOfTheJedi'' is the only reason the Rebels won. If he didn't pull a BigDamnHeroes moment by bringing [[RockBeatsLaser an army of Ewoks to fight the Imperials]], the Rebels would never have destroyed the shield generator and never would have destroyed the second Death Star. The Rebels only met the Ewoks at all because of a Scout Trooper who knocked Leia off of her speeder bike, leading to her befriending them while the others searched for her. If he had aimed a little higher, none of the above would have happened (how appropriate that the Empire's downfall is ultimately caused by the ImperialStormtrooperMarksmanshipAcademy).
** Anakin is the Instigator of his own doom. If he hadn't finished that protocol droid he had started in ''The Phantom Menace'', things could have been very different. One possible unfolding: R2-D2 would have never been sold to the Lars family without C-3P0's endorsement, thus R2 stays with the Jawas, R2 gets vaporized when the detachment of Stormtroopers find the sandcrawler, and Leia's message never reaches Obi-Wan.
** Darth Maul, for all [[EnsembleDarkhorse his popularity]], does precisely one thing in ''Film/ThePhantomMenace'': kill Qui-Gon Jinn. Except that by doing so he ensures Anakin is taught by a newly-Knighted Jedi instead of a wise Master with decades of teaching experience, which plays a huge role in his frustration with the Jedi Order and inability to deal with his phenomenal powers, which in turn plays a huge role in his [[ForegoneConclusion eventual]] [[FaceHeelTurn fall]] and transformation into [[DarkLord Darth Vader]].
* In ''Film/RobinHoodPrinceOfThieves'', his blind manservant Duncan gallops into Sherwood Forest in order to tell his master that Marian has been captured by the Sheriff; only for the bad guys to follow him straight to the outlaws' hideaway and start to massacre everyone there. Beyond getting ushered about by either Robin or Marian, it's the only thing he ever does in the movie.
* In ''Film/WrongTurn4BloodyBeginnings'', a prequel to the ''Film/WrongTurn'' series, one of the characters beg someone not to kill the inbreeds. They spare their life, but in return are responsible for nearly ''every single death'' in the films.
* In ''Film/TheLordOfTheRings: The Two Towers'', at least in the film version, Faramir is one. He is prepared to shoot and kill Sméagol for entering the Forbidden Pool and seemingly allows Frodo to call him out of the pool, but immediately captures him upon his exit. Sméagol thinks Frodo lied to him and, enraged by this apparent betrayal, regresses into his Gollum persona and starts plotting his and Sam's deaths for the sake of retrieving the Ring. In the director's cut, the honor goes to Sam: he spends the whole movie antagonizing Sméagol, so when he tries to explain to him at the end that his capture was not Frodo's decision, Sméagol is quite obviously unconvinced.
* In ''Film/TheEliteSquad'', there's the unknown journalist who takes a photo of Matias and inadvertently reveals the fact that he's a cop to the drug dealers. It ruins Matias's relationship and leads to another character's death.
* The Creator/ShirleyMacLaine comedy ''Film/WhatAWayToGo'' could alternately have been titled ''Unwitting Instigator Of Doom: The Movie'', with [=MacLaine's=] character being widowed four times after her entirely well-meaning suggestions inevitably, relentlessly, snowball into her current husband getting killed in some bizarre fashion.
* ''Film/XMenFilmSeries'':
** ''Film/XMenDaysOfFuturePast'': Mystique's plan was simply to avenge a number of dead mutants by murdering the man who had abducted them and experimented with their corpses. That man had projects, rejected by the Congress, to build powerful robots to kill mutants. His death proved his point, that mutants were an actual menace, and so his projects were restored and continued. The Sentinels would prove so deadly and effective that they would cause the apocalyptic future seen at the beginning of the story. Of course, Mystique had never intended any of that; all she wanted was plain revenge.
** ''Film/XMenApocalypse'': After mutants became public knowledge in 1973, [[https://www.youtube.com/watch?v=pastin69D5c a cult was formed to worship En Sabah Nur,]] and Agent Moira [=MacTaggert's=] investigation inadvertently awakens him because his followers always cover up the entrance to his resting place, but she had left it exposed to sunlight, which reanimates him.
* In Creator/AkiraKurosawa's ''Film/TheBadSleepWell'', Nishi's revenge plot is scuppered by his father's well-meaning widow, who innocently reveals his real identity to one of the men Nishi wants to destroy.
* In ''Film/ANightmareOnElmStreet4TheDreamMaster'', Elaine Parker not only was responsible for her daughter Kristen's death (she put sleeping pills in Kristen's drink), but thanks to that happening it gave Freddy the opportunity he needed to successfully establish a link to the rest of Springwood's teen populace. So basically every death from this movie onward is because of her. Nice job, Elaine.
** The parents of the Elm Street series are this as a whole, as are the cops. Everyone was so desperate in catching the child killer that someone forgot to sign the warrant for his arrest, leading Freddy to be released from prosecution almost immediately. Enraged, the parents chased Freddy to the boiler chamber where he killed his victims and set the place on fire with him still inside. To their credit, the had no idea that doing that would turn him into something much worse than a child-killer.
* Linda in ''Film/BurnAfterReading''. She sends Chad to Harry's house where he winds up dead, then sends Ted over to find what happened to Chad (who then ALSO ends up dead), then accidentally scares Harry into fleeing the country when she mentions Chad's disappearance in a conversation with him.
* Evey in ''Film/TheMummy1999'' merely was curious about what was in the Book of the Dead. Little did she know that reading aloud from the first page would resurrect Imhotep and bring about the ten plagues of Egypt. This is lampshaded in the sequel where Evey wants to open a sacred chest and Rick reminds her of what happened when she read the book.
* ''Film/SleepawayCamp'':
** Craig and Mary-Ann, the two teens in the opening who [[spoiler:accidentally cause the boating accident that kills most of the Baker family and kicks off the entire franchise.]]
** A less innocent example would be [[spoiler:Aunt Martha]]. True, [[spoiler:her forcing Peter to adopt the identity of his dead sister was horrifying and abusive]] but she probably didn't expect it to [[spoiler:escalate to serial murder]].
* ''Film/ItTheTerrorFromBeyondSpace'': Calder dumped some empty crates and other assorted trash on Mars and forgot to close the rocket's airlock up until it was almost time to launch -- which was a long enough time for the alien that killed (almost) every member of the ''Challenger 141'' to get inside the ''Challenger 142'' and continue its rampage with fresh victims.
* Snoop, the airport sniffer dog from ''Film/BabePigInTheCity'' falsely detects that Babe and Esme are carrying illegal substances. Thanks to the interrogation that he brought upon them they miss their flight and are forced to stay in Metropolis. It is here where the film's plot really starts to kick in.
* In ''Film/BackToTheFuturePartII'', a man from 2015 makes an offhand comment to Marty [=McFly=] about using knowledge of the future to bet on sports games. The end result is the Biff-horrific 1985 that Doc Brown and Marty return to.
* Kenny Linder from ''Film/TheFastAndTheFurious''. If he hadn't accidentally killed Dominic's and Mia's father in a racing crash, Dominic wouldn't have beaten him savagely with a wrench and gotten himself banned from racing. And then he wouldn't have turned to hijacking trucks to fund his street racing. And then Brian wouldn't have gotten involved, etc. In short, Kenny Linder is indirectly responsible for the ''entire series''.

* In the former trope-naming incident, from the Literature/SherlockHolmes story ''The Final Problem'', a Swiss messenger in Moriarty's employ catches up to Holmes and Watson with a message saying that an Englishwoman at the hotel they're staying at is on the verge of death and wants to see an English doctor. Watson obediently returns to the hotel, unknowingly [[spoiler:leaving Holmes to face Moriarty alone at the edge of Reichenbach Falls, apparently leading to both of them falling to their death]]. However, it is implied that [[spoiler:Holmes knew all along what was going down but saw no reason to put Watson at further risk.]]
* ''Literature/ASongOfIceAndFire'':
** Catelyn Stark. ''Twice'', but [[spoiler:releasing valuable prisoner Jaime Lannister in an attempt to get her daughters back from the Lannisters]] is more cited than [[spoiler:kidnapping Tyrion Lannister, believing him responsible for the attempted murder of her son on the word of her UnluckyChildhoodFriend Petyr Baelish]], Despite the fact that the Tyrion incident was the casus belli of the civil war that has made the entire world turn to shit ever since.
** Fans often cite [[spoiler:the release of Jaime]] as a crucial step leading up to the Red Wedding, but there are parts of the text suggesting that said wedding was already being planned before it happened. Both Lord Tywin Lannister and the Starks's [[spoiler: treacherous ally Lord Roose Bolton]] appear to be planning something around the time of his release.
*** For that matter, Rob perhaps would have kept his word to the Freys thus negating the whole need for a Red Wedding if he hadn't grown up seeing his otherwise loving mother turn into an WickedStepmother around the [[HeroicBastard sole proof of her husband's infidelity]].
** The irony of Catelyn is that, in most other fantasy worlds, she and Ned would be the most sympathetic characters in the entire story, and the clear virtuous protagonists of the piece. In the CrapsackWorld that they live in, though, they are either directly or indirectly the cause of something like 90% of the tragedy that follows.
** Also Sansa Stark with the whole Lady affair, or running off to Cersei when she did. Forgiven by many only because of [[TheWoobie what happened to]] [[BastardUnderstudy her after that.]]
** When she was a girl, Lysa Tully was in love with her father's ward Petyr Baelish, who was light-years below her in social status so a marriage was impossible. Also, he was in love with her older sister Catelyn. So one night after watching Petyr dance with Cat and get very drunk after Cat wouldn't kiss him, [[spoiler:Lysa crept into Petyr's bed in the dark and had sex with him. She told him she loved him and wanted to marry him, while letting him think she was Cat]]. Shortly after this, Cat's [[ArrangedMarriage engagement]] to Brandon Stark was announced and (understandably from his point of view) Petyr challenged him. Short scrawny 15-year-old Petyr nearly died fighting tall strong 20-year-old Brandon and was promptly thrown out for this and for [[spoiler:getting Lysa pregnant]]. This humiliation was Petyr's StartOfDarkness, turning him into the villain responsible for [[spoiler:the entire civil war - with Lysa manipulated into lighting the first fuse]]. Well done, Lysa!
** Rhaegar Targaryen's abduction on Lyanna Stark set the ball rolling on a chain of events that ultimately brought about both of their deaths, the fall of the Targaryens from power and a long generation enmity among several Houses who were affected by the war.
* ''Literature/{{Discworld}}''
** In ''Discworld/TheColourOfMagic'', when Twoflower, the Disc's first tourist, enters Ankh-Morpork he ends up triggering a brutal brawl between the thieves, assassins, and businessmen when he oh-so-innocently begins paying everyone with solid gold coins, unaware of how valuable gold is there (it's a very common metal in his homeland). At one point he sells an insurance policy to the [[BadGuyBar Broken Drum]], and the resulting attempt at InsuranceFraud inevitably leads to a giant fire that consumes the entire city.
** Twoflower does it again in ''Discworld/InterestingTimes''; after returning home, he wrote a book on his experiences around the Disc. His novel, "What I Did On My Holidays" ends up provoking the oppressed people of the Agatean Empire to revolt. When Twoflower laments that he wasn't trying to stir up trouble, Rincewind the Wizzard mentally notes that Twoflower never ''intends'' to cause trouble.
* ''Literature/HarryPotter'':
** Bertha Jorkins in Book 4. Doesn't appear 'on-screen', doesn't have any speaking roles, dies long before Book 4, but is absolutely crucial in giving the BigBad the capacity to put together his EvilPlan for the book--[[spoiler:she worked for the Ministry's Sports Department, so she knew about the Triwizard Tournement. She then went on holiday to Albania, where Voldemort was lying low with Wormtail. She happened to bump into Wormtail and recognised him, and then she was subjected to lots of tortures and MindRape to make her a source of information to Voldemort. It didn't help that she had coincidentally discovered Barty Crouch Jr.'s existence, either.]]
** Marietta Edgecombe. She revealed the existence of Dumbledore's Army, thus leading to Dumbledore having to flee Hogwarts and Umbridge taking over. [[spoiler:This also indirectly led to Sirius's death, because had Dumbledore remained at Hogwarts, when Harry had that dream about Sirius being captured by the Death Eaters, he would have gone to ''him'', instead of playing into Voldemort's hands. [[ArsonMurderAndJaywalking It was also a key factor in Harry's breakup with Cho Chang.]]]]
** Remus Lupin in ''Prisoner of Azkaban''. [[spoiler: If he'd remembered to take his potion before the climactic confrontation, he wouldn't have been a threat when he became a werewolf, and could have continued to concentrate on keeping Pettigrew from getting away. And if Pettigrew hadn't gotten away, and had been turned in to the authorities, Sirius would have been cleared of his murder charges and would no longer have to be a fugitive, meaning he could have a closer relationship with Harry. And if he'd had a closer relationship with Harry, Voldemort wouldn't be able to use their separation to trick Harry, and Sirius wouldn't have ended up dead.]]
** In the ''Literature/FantasticBeastsAndWhereToFindThem'' textbook, the creature the Quintaped is rumoured to have been created by one of these. Legend has it that one island had two feuding families. One family transformed the other into monstrous five-legged creatures -- who then proceeded to massacre their rivals.
* In ''Literature/BattleRoyale'', [[spoiler:just as Shinji is about to pull off his plan to escape the Program, a fellow student, Keita Iijima, shows up, oblivious to what's going on, and accidentally ruins the entire plan, getting everyone involved killed.]]
* ''Literature/CatsCradle'' has whoever failed to perform proper maintenance on the fighter plane which crashed into the side of the castle.
* Lucy's mother in ''Literature/{{Dracula}}'' is partly responsible for killing Lucy by [[spoiler:opening the window and removing the garlic so that Dracula can get into the room]].
* In ''Literature/TheWiseMansFear'', [[TheDreaded The Cbaeth]] creates these by acting as a malicious oracle or saving people's lives.
* Jacob in ''Literature/TheRedTent'' Because he demands an outrageous bride price for his daughter (after a [[DoesNotUnderstandSarcasm sarcastic]] comment by Joseph), because of a combination of greed and OverprotectiveDad factor, his sons murder Dinah's TrueLove, and all the other Shechemite men. Jacob [[WhatTheHellHero calls his sons out on it]] and dies [[MyGodWhatHaveIDone full of regrets]].
* Curley's wife from ''Literature/OfMiceAndMen'' wanted to have a friendly conversation with Lennie, despite George's orders to Lennie to stay away from her. She eventually took advantage of Lennie's fondness for soft things, and invited Lennie to touch her hair; this soon led up to Curley's wife getting scared and beginning to scream, which in turn made Lennie scared that George would hear her so he squeezed her hair tighter. Guess who winds up with her neck broken. The death of Curley's wife quickly led up to the novel becoming a ShootTheShaggyDogStory.
* Inverted in the ''StarWars'' novel ''Literature/DeathStar.'' Two utterly trivial characters from the first film (the guard who says, "Close the blast doors!" too late, and the gunner who says "Stand by... stand by....") turn out to have [[spoiler:chosen to let Han Solo and Chewie get away, and chosen not to fire on Yavin, because they'd started to have doubts about the Empire. If not for them, the Rebellion would have been crushed.]]
* ''Literature/InDeath'': This trope has happened a few times. ''Vengeance In Death'' had a brilliant plan to catch the murderer ruined by a robot poodle that caused a chain reaction of events that caused the cops to reveal themselves and for the murderer to spot them and run for it. ''New York To Dallas'' contains two instances of this. The first one had a brilliant plan to catch the murderer's partner ruined by a dog that caused a kid to almost get run over by a car, a cop having to save the boy's life and reveal himself as cop, causing the murderer's partner to spot them and run for it. That instance got subverted by the partner getting caught despite a chase anyway. The second instance had the cops closing in on the murderer, only for the murderer to get away. How? The murderer was out shopping when he overheard a conversation between staff member and a stock boy about cops. The staff member recognized an undercover cop working in the area and he was just telling the stock boy about how this cop came to a criminology class and how cool he is. The murderer naturally chose to run for it. Clearly these minor characters would not get a lot of sympathy from readers.
* ''Literature/HaloContactHarvest'':
** A shard of Mendicant Bias reveals to the future High Prophets that [[spoiler:humanity are the heirs to the Forerunners]]. Realizing that this revelation would cause the Covenant to collapse, the Prophets decide that [[spoiler:humanity must be wiped out to cover this up]]. If not for Bias, the Human-Covenant War would have never become so vicious (or even started), and it's possible that none of the ''Franchise/{{Halo}}'' games would have even happened.
** A Huragok (aka Engineer) invents a farming vehicle as a gift for humanity. His Brute overseers find out what he's been doing, and turn his invention into a weapon; this is the origin of the Brute Chopper.
* ''Literature/CiaphasCain'', HERO OF THE IMPERIUM, has his own personal version of this trope in Toren Divas who manages to be both his best and [[TheFriendNobodyLikes most hated]] friend. The best example is in the starship at the start of ''Death or Glory'': while Cain and Jurgen struggle to get out of a room where the hull has been breached, Divas' attempts at being over-dramatic knock some guardsmen off balance as they hold open the emergency doors, trapping Cain and Jurgen and forcing them to get into a lifepod, making planetfall deep in ork-held territory. This sets off the whole plot, though as that involved Cain and Jurgen's flight to safety snowballing into liberating the planet, the people of Perlia would probably have thanked him.
* Literature/TrappedOnDraconica: Yusef tells Gothon where the Eastern Alliance's HQ is and how to defeat their army. He thinks this will lead end the war with minimum casualites on both sides. This is his only action in the entire story.
* ''Literature/TheHitchhikersGuideToTheGalaxy1'' contains Arthur Dent making a comment about his difficult lifestyle... that gets sucked through time and space to the conference table of two armies, is interpreted in their language as the worst thing to ever say, and ultimately sparks a thousands-of-years-long war between the two that devastates all in its path and kills thousands. Then the two realise the problem and [[EnemyMine team up to attack the Earth]] [[spoiler:where they are promptly eaten by a small dog]]. Indeed, this sort of thing is hinted by the book to happen all the time, potentially making ''everyone'' this trope.
* In ''Literature/TheLastBattle'' Shift the Ape and Puzzle the Donkey find a lion skin in the waters of Caldron Pool, which leads to the former convincing the latter to dress up in it and pose as Aslan. Their actions kick-start the End of Narnia, but the source of the lion skin is casually mentioned as being a hunter up in the Western Wilds who killed and skinned a lion weeks before.
* Supreme Chancellor of the Republic Tarsus Valorum in the [[Literature/DarthBane Darth Bane trilogy]] ended up doing this. After the New Sith Wars ended with the Battle of Rusaan, he passes the Ruusan Reformations, which among other things disbands the Republic's military and also forces the Jedi to take a more advisory role in the Republic rather than the protectors that they used to be. This would later play into Palpatine's hands when he took advantage of Jedi Master Sifo-Dyas's contracted clone army to create an army unquestionably loyal to him, rather than thinking men that might form their own opinions. He facilitated the rise of the Empire a thousand years later, though he couldn't have known it at the time.
* ''Literature/LookingForAlaska'': Numerous characters blame themselves for the title character's [[spoiler: fatal car accident]], but the one who initially sets the ButterflyOfDoom in motion is her boyfriend Jake, who [[SmallRoleBigImpact barely appears in the story otherwise]]. As Alaska and Miles are about to have TheirFirstTime, she gets a call from Jake. While taking the call she absentmindedly doodles a white flower, as she often does, [[spoiler: which suddenly reminds her that it's the anniversary of her mother's death and for the first time in her life she forgot to put white flowers on her grave. The realization that she not only missed the anniversary, but spent the last few hours of it cheating on her boyfriend, sends her into a FreakOut, and she tears out of the school, stinking drunk, gets into her car, and crashes trying to race to her mother's grave to make things right]].
* ''Literature/DebtOfHonor'':
** A pair of improperly-galvanised fuel tanks explode when the cars they're in get into an accident, starting a series of events that lead to disaster. One character who knows about ThePlan likens it to the assassination of Franz Ferdinand. For added sick irony, for all the furore they cause over alleged Japanese safety defects, the problem can be traced to a worker at an ''American'' factory who smelled a rat but didn't think it was worth taking a second look at and just let the defective fuel tanks be installed rather than giving them a thorough inspection.
** George Winston, who sold off the Columbus Group to Yamata and unintentionally gave the man a vital foothold for his plan.
* Almost every adult who ever happened to be the guardian/s of the Baudelaire Children in Literature/ASeriesOfUnfortunateEvents. The worst example of the lot would have to be Mr. Poe, however, who in every book has been rightfully warned by the children about Olaf performing a new scheme for every book, refusing to believe them, being proven wrong, escorting them to the next available guardian, and repeating the cycle for up until The Vile Village, where the cycle only stops because [[spoiler: the Baudelaires are wrongfully accused of murdering Jacques Snicket, who the villagers thought was Count Olaf.]]
* [[spoiler: Clement Massey]] from ''[[Literature/DirkPittAdventures Night Probe!]]'' robs a train station and prevents the conductor from stopping a train from going over a weakened bridge and plunging into the Hudson River. He had no idea that the train was carrying a document that would [[spoiler: merge the United States and Canada into a single country]]. Subverted when it turns out [[spoiler: the train was actually rerouted into an underground quarry to be robbed with more time.]] Doubled Subverted when [[spoiler: Massey and the train's crew and passengers are trapped in the quarry with no escape.]]
* ''Literature/TheStormlightArchive'': Eshonai, a Parshendi girl who became their last general, accidentally caused most of the plot of the series by stumbling upon the Alethi while she was out exploring, which led to the Alethi king trying to [[spoiler:turn them into Voidbringers]], which led to the Parshendi assassinating him, which led to the Alethi declaring war on them, which led to the Parshendi desperately [[spoiler:turning themselves into Voidbringers, summoning the Everstorm, and starting the next [[TheEndOfTheWorldAsWeKnowIt Desolation]]]]. Admittedly [[spoiler:the Everstorm and the Desolation]] likely would have happened eventually anyway, but she feels understandably guilty about the exact events leading up to it.


[[folder:Live-Action TV]]
* ''Franchise/{{Buffyverse}}'':
** Wesley in ''Buffy'' overheard that Faith accidentally killed someone. The rest of the team is already on-board with helping her deal with her issues and giving her the support and acceptance she needs in order to not fall to TheDarkSide. Wesley's response on the other hand is to call in some goons and try to ship her to England to be locked away forever. By the end of the episode, she doesn't trust any of them, resents all of them (because she thinks they want her to just be like Buffy), and has taken a job as the BigBad's [[TheDragon number two]].
** Angel. Wolfram & Hart has a stated mission of bringing Angel to their side. Sound pretty far-fetched? The road to Hell is paved with good intentions.
* In the second season of ''Series/CriminalMinds'', [[spoiler:the team was trying to bring in a delusional war veteran who is panicking because the construction sounds like the war zone. Now, they find him and have swat surround the suspect as they coaxed him to surrender. They tell these construction men nearby in plain view of the drama to stop working until they are done, but naturally the men resume construction before the suspect is apprehended. This causes the suspect to panic and he runs towards a kid on a bike, forcing a SWAT marksman to shoot him.]] [[WhatTheHellTownspeople The construction crew couldn’t have waited 30 minutes for the damn police, SWAT, and FBI to finish?]]
* ''Series/DegrassiTheNextGeneration'' gives us Paige Michalchuk, who gets her friend Terri drunk before a dance and ends up with the guy Terri wanted instead. Later on, Terri thinks she'll never find a man and ends up with abusive boyfriend Rick. Later, Rick comes back and Paige gets to be an inversion of this trope, albeit ultimately subverted because someone else pisses Rick off enough that he starts shooting people.
* ''Series/GameOfThrones'': Robb's infatuation with Talisa results in the Freys, Karstarks and Boltons breaking with House Stark, leading to the extermination of the Starks and their loyal bannermen at the Red Wedding.
* In murder mystery ''HarpersIsland'', nine-year-old Madison is kidnapped by the AxCrazy BigBad, John Wakefield. When rescued, she goes along with the lies Wakefield told her to tell the others -- specifically that it was the Sheriff who kidnapped her. ''Even though she knew that Wakefield was evil.'' This gets several people killed.
* Narrowly {{averted}} by Princess Mithian on ''Series/{{Merlin}}'', who in a bid to impress KingArthur, shoots a young deer in the forest. Unbeknownst to her, the deer is actually [[BalefulPolymorph Guinevere under an enchantment]]. Only Merlin realizes what she's done and returns to the forest at night to hunt for Gwen and heal her from her injury.
* ''Series/PowerRangersRPM'': To escape from the research facility she spent most of her pre-series life confined to, Doctor K decided to release a sentient computer virus her captors had her design for them. She intended to keep it to the facility's computers, but two guards caught her before she could finish installing the firewall, ignoring all her protests. Cue the destruction of human civilization outside of Corinth City. [[HolyShitQuotient In]] ''[[HolyShitQuotient Power Rangers]]''.
* Due to a lot of TimeTravel and AnachronicOrder being involved, the Blue Senturion in ''Series/PowerRangersTurbo'' is often accused of being this, the negative result being Zordon's death. He'd come back in time a thousand years to warn of a massive war a year later -- but the villains intercepted him, took the message, then wiped it from his memory, resulting in the evil side of the war being ''way'' more prepared than the good guys.
** Of course, time travel being what it is, no one really knows how different the end result would have been.
* In ''Series/PowerRangersDinoCharge'', Keeper tricks Fury into retrieving the Energies for Sledge, only to find that Keeper [[SomebodySetUpUsTheBomb swapped the Energems with his crystal bomb]]. It causes Sledge's ship to drift into space and his asteroids to fall to the earth, causing the extinction of the dinosaurs.
* In the BBC's ''Series/RobinHood'' the titular character is trying to make a tentative alliance with Isabella, the new Sheriff of Nottingham (and his ex-girlfriend) despite the grumblings of the other outlaws. His reasoning is sound, and after striking a deal with her he asks Little John to escort her safely home. For no reason whatsoever, John decides to tell Isabella that Robin "has eyes for Kate" (a fellow outlaw). This achieves nothing except [[GreenEyedMonster pissing Isabella off]] and [[IHaveBoobsYouMustObey leading her to doubt that she has any kind of power over Robin]]. She turns on him at the next available opportunity which leads directly to two outlaws' deaths. [[NiceJobBreakingItHero Nice job antagonising]] the valuable ally, John.
* Octavia in ''Series/{{Rome}}'' may have been indirectly responsible for the deaths of Julius Caesar and [[spoiler:Vorenus' wife. Octavian told her about Vorenus' wife's affair and told her it was a secret. For no reason whatsoever, Octavia told Servilla this. When Caesar's enemies planned to assassinate him, this information became crucial and was used to drive Vorenus (who was supposed to guard Caesar) away, leaving Caesar as a sitting duck. Meanwhile, Vorenus confronted his wife and she ended up killing herself out of honor.]] And of course, there is the whole second round of war and murder until it is settled who succeeds Caesar, which ends with the establishment of TheEmpire.
* ''Series/OnceUponATime'':
** Baelfire is one of the main causes of the plot in the show. His father Rumpelstiltskin became the Dark One to protect him from becoming a child soldier. [[spoiler:His disappearance into another world]] is what caused Rumpelstiltskin to search for a land without magic - and so create a curse dooming the entire populations of multiple worlds to years of misery. All of Rumple's deals and schemes, including turning Regina Mils into a "monster," was part of his plan to [[spoiler:find Baelfire.]]
** Also, Queen Eva started the bitter and long feud between Cora, Regina and Snow's family because when she was young and a SpoiledBrat, [[spoiler:she exposed Cora as an unwed mother to keep her fiancee King Leopold from marrying her. Then she tripped Cora, claimed that Cora hurt her, and thus began Cora's long vendetta against the nobles and in particular, her family.]]
** Likewise the palace gardener Jonathan pretended to be the prince, and seduced Cora while she was working in a tavern. Thinking they would marry, she slept with him [[spoiler: and got pregnant with Zelena, the Wicked Witch of the West]].
** In the first season finale, Jefferson decides to [[TheDogBitesBack get revenge on Regina]] by exploiting Rumpelstiltskin's love for Belle. In doing so, [[spoiler:Rumpelstiltskin sends the Wraith against Regina in his ''own'' revenge which results in it (along with Emma and Mary) to be banished to the Enchanted Forest. The following events led to [[BiggerBad Cora]] finding her way to the real world and set off almost all the events of Season 2, and by extension, the rest of the series.]]
** Mr. Gold's [[KickTheSonOfABitch pursuit for revenge at the end of season 3]] winds up severing the ties with that arc's BigBad and her AmplifierArtifact. This results in the magic triggering her [[spoiler:TimeTravel spell which got Emma and Hook trapped in the past where they, [[NiceJobBreakingItHero along with several other things]], end up bringing with them a golden urn that spills over, leading to the release of Elsa and the first half of Season 4's plot]].
** The season 4 crossover arc with ''Disney/{{Frozen}}'' is another case, according to the episode "The Snow Queen". Basically, the Duke of Weselton tried to seduce his betrothed Helga's sister Ingrid. This caused Helga to be killed by Ingrid, which causes Ingrid's other sister Gerda to develop a fear of her family's magic, which led to her and her husband seeking to find a way to treat Elsa's magic, and caused the events of the movie to happen and the events of the ''Frozen/OUAT'' crossover to happen.
** In a way, Rumpelstiltskin's pursuit to sever his ties to [[spoiler:the darkness that binds his heart]] in Season 4 is what leads to Season 5. [[spoiler:Eventually the heroes get the darkness out of him, but said darkness decides to get a new host, Emma. This results in the Dark Swan arc which, because of a long chain of events, ends in the Underworld Arc.]]
* Valerie in the ''Series/SabrinaTheTeenageWitch'' episode "Sabrina and the Beanstalk". She decides to phone Sabrina to ask about shampoo, which makes Sabrina forget she was supposed to pick up spell ingredients from the Other Realm. When she gets off the phone, the store is closed, so Sabrina substitutes the ingredients for magical jumping beans. When they don't work, she throws them out and a beanstalk grows in the backyard. What's more is that Harvey eats one and gets sent to the top of the beanstalk - where he bumps into a WickedWitch (apparently '''the''' ]][[UrExample Wicked Witch]]) who likes to eat mortals.
* A particularly heartbreaking episode of ''ColdCase'' gave us a girl who had a crush on the VictimOfTheWeek, who was a mentally-challenged teenager. One day alone in class, she tried to kiss him when her [[BastardBoyfriend meathead boyfriend]] walked in and she lied and said ''he'' tried to sexually assault ''her'' so that she wouldn't get a "bad reputation", which essentially caused him to be beaten up by the said boyfriend and his gang of thugs (as well as him only friend, who was embarrassed by him), her parents deciding to file charges against him, he ending up in an institute instead where, due to his alleged sexual deviance, is in the worst tier of the facility where the care for the patients is horrifyingly neglectful, quite frankly. In addition to this, the boy's loving mother (and one of only two people at this point who gave a damn about him) is dying of cancer as all of this is occurring, the boy's [[JerkAss father won't take care of him because of his mental status]] and the boy's [[spoiler:caregiver, who was also dating the mother, takes him from the institute and [[TearJerker rather than have him live a life of loneliness and neglect, has him ran over by a train.]]]] In present day, the girl FINALLY realizes the effect of her actions and is remorseful, but it's still too little, ''way'' too late.
* In ''Series/StarTrekDeepSpaceNine'' Kai Opaka gives Commander Ben Sisko one of the Tears of the Prophets and asks him to find the Celestial Temple to help reunite the Bajoran people. What she didn't realize was that the Celestial Temple was actually a wormhole to the other side of the galaxy. Its discovery by the Federation lead to disastrous first contact with [[TheEmpire the Dominion]] and eventually the most devastating galactic war of the Trek verse.
** Then again that war led to the further entrenching of the alliance between the Federations and the Klingons; a revolution against the Cardassian military leadership; and brought the Romulans to the table in a productive way. In the long run the galaxy may be better off, but at what cost?
* ''Series/BandOfBrothers'' has Dick Winters and Moose Heyliger deciding to take a stroll one evening just to check on the men's morale. A sentry mistakes them for the enemy and [[UnfriendlyFire shoots Moose]]. This results in him being pulled off the line and the incompetent Lt Dike is put in charge of Easy Company - just in time for the horror of Bastogne and the Battle of the Bulge, during which many men lost their lives. The sentry in question was quickly transferred to another regiment for his own safety.
* In ''Series/HouseOfCardsUS'', President Garrett Walker promised to make Frank Underwood his Secretary of State in exchange for Frank's help in the 2012 election. After it was over, Walker reneged on his promise, causing Frank to seek revenge. Revenge that entails multiple murders, ruining the lives of any number of people, and finally Frank stealing Walker's presidency out from under him. And that's just what Frank does to ''get'' to the Oval Office. Once there, he firmly establishes himself as a PresidentEvil that puts his own ambition before the needs of the country.
* Halfway through season 3 of ''Series/PersonOfInterest'', Simmons kills [[spoiler:Carter]] in revenge for the fall of HR. This causes Reese to go into a TenMinuteRetirement, requiring Fusco to track him down and drag him back to New York. This leaves Team Machine critically understaffed during their next case, while allows Decima to get a hold of the source code of the Samaritan AI, which would become the BigBad of the next two seasons. That's right: a revenge murder by a DirtyCop at the wrong moment nearly caused the entire world to be taken over by an evil supercomputer.
* ''Series/VeronicaMars:''
** At Shelley Pomroy's party, Madison Sinclair was given a drink she didn't want, so she spit in it and gave it to Veronica. She didn't know that the drink was dosed with GHB which led to Veronica getting raped. When Veronica blasts her for it, she still doesn't see how it's her fault.
** During a debate for the election for sheriff, Don Lamb accuses his opponent Keith Mars of being this for the recent bus crash. As a beat cop, Keith once pulled over the bus driver for DUI but let him go. It later turns out that the bus driver was innocent of the crash. In a bit of subtle irony, Lamb himself is the Unwitting Instigator of Doom because if he had [[spoiler: investigated Veronica's rape, he could have arrested Cassidy Casablancas before he could trigger the bus crash.]]
* ''Series/{{Arrow}}'': One day, a young thug named Danny Brickwell was undergoing his initiation for a gang in the Glades. The initiation process required him to kill someone to get in. He chose a brunette woman who ran the free clinic there. That woman? [[PlotTriggeringDeath Rebecca]] [[TheLostLenore Merlyn]]. After that, it was just one domino after another.
* ''Series/AgentsOfShield'': Way back in the ancient past, some Kree scientists decided to perform experiments on a bunch of primitives on a backwater planet to create expendable troops for their empire. The experiment was deemed unsuccessful and the Kree left. Thousands of years later, that minor experiment led to essentially everything that happened, good and bad, in the MarvelCinematicUniverse.

* Nena's song "99 Luftballons" (and its English version "99 Red Balloons") tells a story of a young couple who release 99 balloons to celebrate their love. The balloons are picked up by military radar and trigger a war that levels the city.

[[folder:Pro Wrestling]]
* Wrestling/ChrisHero was kicked out of Wrestling/{{Chikara}} in 2007 and all relating to him [[UnPerson was scrubbed clean from view]] but his actions continued to have an effect on the promotion regardless. It was his acquisition of the Eye Of Tyr from Dr. Cube of Wrestling/KaijuBigBattel that allowed for Wrestling/UltraMantisBlack's Order Of The Neo Solar Temple to gain power and the BDK after them, and [[Wrestling/HunterJohnston Delirious]] taking up the ways of a rudo after that, and [[Wrestling/{{Hallowicked}} the]] [[Wrestling/{{Frightmare}} rest]] of Incoherence going bad after that. The effects of manipulations also lead to the rise of STIGMA in his absence.
* {{Wrestling/Paige}} accidentally bumped into Wrestling/SummerRae after winning a match. This act of disrespect caused the ring announcer to snap and attack Paige, thereby establishing herself as the new top heel Diva on NXT.
* Summer Rae later became one herself. She corrupted Sasha Banks in order to get an ally for herself and form the Beautiful Fierce Females. Little did she know that Sasha would become an even more effective villain than her - and eventually the NXT Women's Champion. Everything Sasha did as The Boss stems from that one ReasonYouSuckSpeech. And for good measure, Wrestling/RicFlair's daughter Wrestling/{{Charlotte}}, who they brought into the group early on as a stab against Wrestling/{{Bayley}}, has also advanced much father than Summer since then. As of summer 2016, Summer Rae essentially helped create the history behind the main feud for the WWE Women's Championship, and herself has nothing to show for it.
* The signing of Wrestling/KurtAngle can be pointed to an indirect source to all of Wrestling/{{TNA}}'s current issues thanks to two things it caused. The most direct one was bringing in his then-wife Karen into the promotion. After she filed for divorce and they separated, she started dating Wrestling/JeffJarrett -- Dixie Carter found out, freaked, stripped Jarrett of all booking power and sent him home. Since most wrestlers saw Jarrett as the real boss, this allowed her to insert herself into a position of power backstage (she was only supposed to write the checks). The other one is the precedent it set; despite being by far and away the best signing TNA has ever made (with Wrestling/{{Christian}} and Wrestling/{{Sting}} being relative close seconds), Kurt's arrival allowed a floodgate of older wrestlers that entered the promotion and soaked up the spotlight from the younger talent people wanted to see. Eventually, this led to bringing in Wrestling/HulkHogan and Wrestling/EricBischoff, who took that same problem along with all the other ones that made TNA Wrestling/{{WCW}}-lite, and dialed them UpToEleven, ushering in the DorkAge that the company is ''still'' trying to recover from to this day.

* [[http://en.wikipedia.org/wiki/Fred_Merkle Fred Merkle]] was a baseball player for the Giants back in the early twentieth century. In the bottom of the ninth inning in a game against the Cubs, there were two outs and the score was tied, and Merkle was on first base (someone else was on third). Another player scored, scoring a game-winning run, but in the excitement Merkle never actually stepped on second base. Thus, a player for the Cubs stepped on second base and called Merkle out, thus nullifying the run. As this game was played before electric lighting, the game was declared a tie. Thus, the Giants and Cubs ended the season tied for first place, requiring a rematch to determine who would go on to win the pennant. The Cubs won. The sheer amount of hatred directed at Merkle's one mistake was astounding, especially considering that he was far from the only person who cost the Giants the pennant. It wasn't excitement that kept Merkle from stepping on second; the fans stormed the field, and he ran for the clubhouse for his own safety. The game was called a tie after the Cubs player somehow made the play in that mess because they couldn't clear the field. It should also be noted that, since this behavior by the fans was quite common back then, such a force out had never before been enforced under those conditions. All of this really makes Merkle one of the worst cases of MisBlamed in sports history.
* Steve Bartman. As the story goes, the Chicago Cubs were on their way to their first World Series since 1945 when hapless fan Bartman interfered with a foul ball, costing the team a precious out. What gets overlooked is that after the incident, Chicago still led 3-0 with one out in the 8th inning, and could have easily won the game if not for a bout of spectacular incompetence: a wild pitch, an error on an easy ground ball that could have ended the inning, two intentional walks that backfired to the tune of four runs allowed, and other hard hits. The tense 3-0 game became an 8-3 laugher. Oh, and that was only Game 6 of a seven-game series; the Cubs could have still made the World Series by winning Game 7, at home, with their best pitcher going. That didn't work out either.
* Similarly, Bill Buckner's epic error in 1986. History notes that the Red Sox had the Mets down to their final out, and three times down to a final ''strike'' that would have brought Boston a long-awaited championship. Buckner's famous gaffe was made possible only by three consecutive singles, a wild pitch, and pitcher Bob Stanley failing to recognize that baserunner Ray Knight had strayed so far from second base he could have been picked off easily. And, like the above example, this loss only tied the series at 3-3; the stunned team could have regrouped and won the next day, but did not. Furthermore, the game was tied (due to the wild pitch mentioned above) when Buckner made the game-ending error. Had he made the play, the game would have continued another inning, making this another case of MisBlamed.
* In the bottom of the ninth inning of game six of the 1985 World Series, umpire Don Denkinger called Kansas City Royals baserunner Jorge Orta safe on a close play at first base. ABC's replay showed that St. Louis Cardinals pitcher Todd Worrell managed to get to first base and took the toss from first baseman Jack Clark at the base before Orta reached it. Cardinals fans will blame this call for costing them the championship and Denkinger was hounded by them for years. However, Orta was the first batter of the inning. The Royals eventually loaded the bases and it was the fourth batter of the inning, pinch-hitter Dane Iorg, who got the hit that scored two runs to give Kansas City a 2-1 victory. The Cardinals could have still won the series the next night in game seven, but were still unhinged by the events of the previous night and the Royals won 11-0, claiming their first[[note]]and, until 2015, only[[/note]] World Series title. It didn't help that the Cardinals had won the first two games of the series in Kansas City and held a 3-1 lead in the series after five games, making the Royals the first team ever to come back from a 3-1 series deficit after losing the first two games at home. Oh, and Orta wasn't even on base when the winning run was scored...he was thrown out at third on a poorly-executed bunt play.[[note]]This ''also'' ignores the fact that the Cardinals had already benefited from a similar bad call: Royals player Frank White was called out in a close play at second but the replay showed that he, unlike Orta, had actually beaten the tag; the next hitter, Pat Sheridan, drove a single to right field that likely would have allowed White to score from second, more than making up for Orta's scoreless two-base advance.[[/note]]
* For all the flack Lebron James got for the Miami Heat losing the 2011 NBA Championship. it may have been Dwayne Wade that started the collapse. Miami looked to have a 2-0 lead over Dallas when Wade hit a three-pointer to put them up by 15 in the fourth - and he chose to taunt the Mavericks by posing in front of their bench. Dallas mounted a furious rally to win that game, posted another comeback in Game Four and ultimately took the trophy right from under the anointed Heat's collective noses.
* From the American point of view, an unidentified member of the Illinois Highway Patrol [[http://espn.go.com/golf/rydercup12/story/_/id/8444955/2012-ryder-cup-rory-mcilroy-needs-ride-police-make-tee-time who escorted the Northern Irish World Champion golfer Rory McIlroy]] to the final day of the Ryder Cup; [=McIlroy=] was instrumental in Europe's comeback from 6-10 to retain the cup 14.5-13.5.

[[folder:Tabletop Games]]
* ''TabletopGame/MagicTheGathering'': Lamar, a barbarian sentry from ''[[Literature/OdysseyCycle Judgment]]'' who sees Jeska knocking Kamahl's friend Balthor unconscious, and, believing she's killed him, rushes to tell Kamahl, who [[spoiler:[[PoorCommunicationKills attacks Jeska in a fit of rage, mortally wounding her]]]]. This leads to the Cabal finding Jeska and [[ReforgedIntoAMinion saving her life by transforming her into Phage the Untouchable]], kicking off the apocalyptic events of the entire ''Literature/OnslaughtCycle''. Which, as it turns out, led to the fabric of existence being marred so much that temporal rifts began opening across all of the Multiverse (at various points in spacetime, no less); these rifts were revealed to be the causes of some key events that led to the Kamigawa and Mirrodin blocks, and finally culminated in permanently warping the very nature of all Planeswalkers Sparks both currently held and from that point forward. Because one private didn't check the body, the Multiverse was forever changed.

* ZerothLawOfTropeExamples: Romeo's servant Balthasar in ''Theatre/RomeoAndJuliet'', when he brings his message to Romeo telling him of Juliet's death. Sadly, the friar's letter telling him that the death was faked does not get through -- so there are ''two'' Swiss Messengers, the one who delivers the wrong news, and the one who doesn't realize how important the ''real'' news is, and fails to deliver it. Actually seems to have achieved some degree of PopCulturalOsmosis, which runs counter to the norm for an author so prone to EverybodyKnowsThat.
* In Creator/OscarWilde's ''Theatre/AnIdealHusband'', the scatty Lady Markby brings a friend to a party, appearing in two scenes in the first act, and never appears onstage again. Said friend turns out to know their host's dirty secret, thus causing the events of the entire play.
* ''Theatre/CyranoDeBergerac'': Hilariously subverted by De Guiche: he is a villain who unwittingly derails his own plans. In Act I Scene IV, he utters a simple DareToBeBadass to De Valvert, a small but crucial gesture that [[DisasterDominoes sets events in motion that result in]] the derailment of his own plan to [[ArrangedMarriage marry]] Roxane to [[TheBeard De Valvert]] so de Guiche could bully her to be his [[TheMistress mistress]].
* Theatre/{{Sweeney Todd|TheDemonBarberOfFleetStreet}} would never have gone on his murder spree as the Demon Barber of Fleet Street had Anthony not barged into his shop, with Judge Turpin ''right there in the damned room'', in order to inform Sweeney of his plans to elope with Johanna, bombing both plans to hell and making everything worse.
* ''Theatre/{{Brand}}'' has Gerd, a CloudCuckoolander who crosses paths with the main character time and again, prompting his choices for the worse. At the end of the play, she is the one who fires the shot to loosen the lavine that buries the entire community completely (and everybody in it). Justified because she is obsessed by the thought of getting a shot at "the bad priest on the black peak". Whatever that is.
* ''Theatre/IntoTheWoods'': After all the fairytale events, one of the consequences is that the widow of the giant Jack killed comes down seeking revenge against Jack. However, it's during the song "Your Fault" that the other characters learn that they were all indirectly responsible -- the Baker was the one who gave Jack the magic beans in exchange for Milky-White, his wife attempted to give Cinderella an extra bean in exchange for her golden slipper, which she promptly threw away (it was this second beanstalk that the giant's widow climbed down), Red Riding Hood dared Jack to get the harp, which was the point where the giant became aware of Jack stealing their stuff, and the Witch was the one who raised the beans in the first place. All the other characters ultimately agree to [[NeverMyFault blame the Witch for the whole thing]] -- [[FantasticRacism just because she's a witch and therefore an easy target]] -- despite her being by far the least involved.
* As Captain Henry Wirz testifies during the climax of ''Theatre/TheAndersonvilleTrial'', General Sherman's march through and destruction of Atlanta only exacerbated the problems at Andersonville.
* ''Theatre/MissSaigon'': Ellen. Had she not reacted so badly to the idea of taking Tam, Kim might not have felt it necessary to kill herself in order to ensure that they would.

* Literally everything that happened in ''Toys/{{BIONICLE}}'' can be traced back to two characters' actions: Annona, who amplified the Great Beings' pre-existing compulsion to create, which eventually led to the Great Spirit Robot; and the Energized Protodermis Entity, who let the Core War happen and caused Spherus Magna to shatter. While it's debatable exactly how much of this was "unwitting", it's doubtful either of them foresaw just how much of an impact their actions would have.

[[folder:Video Games]]
* In ''VideoGame/{{Bastion}}'' [[spoiler:The ManipulativeBastard who seduced and betrayed Zia]] indirectly caused [[ApocalypseHow The Calamity]] by [[spoiler:driving Zia's father into sabotaging the Calamity and getting the Mancers panicked enough to set it off.]]
* In ''VideoGame/DragonQuestIX'', during a pre-game flashback, [[spoiler:Serena's father is responsible for Corvus' StartOfDarkness by showing up at the worst possible moment lying to the guards that Serena tricked Corvus into drinking a sleeping potion in order to have him sold out to the Gittingham Empire in exchange for their village's safety. Corvus feels that he has been betrayed, and in spite of fulfilling his end of the bargain, Serena's father, [[YouSaidYouWouldLetThemGo and Serena herself, who he was trying to protect]], [[ILied are both still murdered by the soldiers for their trouble]], and Corvus is locked up for 300 years]]. When he is finally freed near the end of the game, [[WoobieDestroyerOfWorlds he intends to destroy humanity in light of the perceived betrayal he suffered]] which has led him to believe that HumansAreBastards. [[NiceJobBreakingItHero Thanks for nothing, old man]].
* ''VideoGame/FinalFantasyX'': So Yuna and her friends have uncovered the truth about [[spoiler:Maester Seymour]], and are getting ready to [[spoiler:send his ass to the Farplane]], when [[spoiler:Trommel]] intervenes and interrupts the ritual. Then, [[spoiler:Trommel, after being confronted with Seymour's wrongdoing ''destroys the sphere of Seymour's father warning about his son's StartOfDarkness'', with the excuse that "the Guado deal with Guado affairs."]] Needless to say, with this action, [[spoiler:Yuna and company are forced into hostile terms with not just the Guado, but ''the entirety of Spira as well'', and the unsent Seymour goes on to attack the party several times, proving to be a deadly recurring villain. The decision does later cause trouble for the Guado when Seymour nearly wipes out the Ronso, leading to the near retaliatory genocide of the Guado in the sequel.]]
* ''VideoGame/FinalFantasyVII'' Professor Gast certainly counts. While he has the best intentions at heart and tries to obtain knowledge to help make the lives of the people better, he released [[EldritchAbomination Jenova]] from its prison, mistakes it for a Cetra, then writes a journal that [[BigBad Sephiroth]] reads that kicks off his [[SanitySlippage descent into darkness]].
* ''VideoGame/MassEffect2'' has a slight case of this in [[DisabledSnarker Joker]]. Shepard ''{{di|sneyDeath}}es'' at the start of the game specifically because Joker refused to leave the Normandy when it was going down in flames. Shepard was forced to pull off a Heroic Sacrifice for him. Despite this, Joker is still a popular character, but it did earn him some haters. (Then again, if Shepard hadn't died in the beginning, Cerberus wouldn't have given Shepard the ''Normandy'' SR-2 and a whole new BadassCrew, and it's unlikely that the Alliance would have been so generous...)
** It stops being an elephant in the room in ''VideoGame/MassEffect3''. In the Paragon post-Thessia conversation, Joker admits that he blames himself for Shepard dying and now being "like, half-robot at this point - no offense, EDI." It also has some surprising long-range consequences for the ending that no one could have anticipated at the time; [[spoiler:because Shepard is a mixture of an organic and a synthetic, s/he can now select the "Synthesis" option, breaking down the barriers between synthetics and organics, but on the down side, "Destroy" will almost certainly kill Shepard along with other synthetics unless the player has enough Effective Military Strength]].
* In the "Invasion of the Firelands" quest chain in ''VideoGame/WorldOfWarcraft'', the players can become one in a rare instance in which they cause disaster without being an UnwittingPawn. Shortly before the attack on the Firelands is about to begin, Hamuul asks the player to investigate a Druid of the Flame nearby. The Druid of the Flame, Leyara, attacks the player and Hamuul, badly burning Hamuul and preventing the protectors of Hyjal from going on the offensive until the player gets enough Marks of the World Tree to unlock the next phase of daily quests.
** There were many people, events and circumstances that caused Garrosh Hellscream to become the BigBad of Mists of Pandaria. But who ultimately introduced him to Thrall, causing him to bring Garrosh out of his HeroicBSOD and make him his successor as Warchief? The Horde players did, while questing in Nagrand, two expansions before Garrosh's rise to power.
** In ''Wrath of the Lich King'', the Horde is betrayed by the Royal Apothecary Society of Undercity, under the command of Varimathras and Apothecary Putress. Who did the legwork for most of their twisted experiments with the New Plague? Three guesses, first two don't count. [[spoiler:Horde players doing all those Apothecary quests all the way back to Vanilla.]]
** Garrosh Hellscream's escape to alternate Draenor is done with the help of a bronze dragon, Kairoz. How does Kairoz manage to open a portal to another dimension despite the bronze dragons losing their powers at the end of Cataclysm? By collecting Epoch Stones from the Timeless Isle to create the Vision of Time, a device that can traverse timelines. And who helps collect those stones? Oh that's right, ''the player''. [[spoiler: This could have even bigger ramifications than previously thought- as well as Garrosh's Iron Horde invasion, Warlords of Draenor seems t be building up to a ''Burning Legion'' invasion of our Azeroth.]]
* In ''VideoGame/FinalFantasyII'', the cowardly Prince Gordon eventually musters the courage to assist the rebellion and departs for his home of Kashuan. Except he departs just when Firion's party needs to enter Kashuan Keep, which can only be opened by a member of the Kashuan royal family or [[SongsInTheKeyOfLock the Goddess's Bell]], forcing Firion's party to detour to the Snow Cavern to retrieve the Goddess's Bell. [[spoiler:Their [[GuestStarPartyMember guide]], Josef, [[HeroicSacrifice doesn't return from the Snow Cavern]].]]
* In ''VideoGame/TheElderScrollsVSkyrim'', Aventus Aretino is a boy who wants to summon [[MurderInc the Dark Brotherhood]] to kill the evil headmistress of an orphanage in Riften. Being the PlayerCharacter, you, naturally, have to do the deed. By doing so, you actually come into contact with the Brotherhood, who want to recruit you. [[spoiler:You can either turn on their leader, silencing what is possibly one of the last branches of the Brotherhood, or you can join them, starting a blood-soaked questline that culminates in you personally killing the Emperor. All because of this little boy's wish.]]
* In ''VideoGame/MetroidPrime'', [[spoiler:the Omega Pirate tried to crush Samus upon death, giving her the Phazon Suit. At first the suit proved useful for the protagonist, even helping her to defeat the eponymous FinalBoss by using the Hypermode ability for the first time. But after the battle, the renmants of the DNA of Samus (and, by extension, that of the Omega Pirate) in the Phazon Suit led to the creation of ''Dark Samus'', which leads to the events of ''[[VideoGame/MetroidPrime2Echoes Echoes]]'' and ''[[VideoGame/MetroidPrime3Corruption Corruption]]''.]]
* [[spoiler:[[VideoGame/GrandTheftAutoIvTheLostAndDamned Ashley Butler]]]], in a cameo in ''VideoGame/GrandTheftAutoV'', [[spoiler:has sex with the violently unstable Trevor Phillips for a quick fix. This leads to the death of Johnny Klebitz, the massacre of the entire Liberty City chapter of The Lost, and Ashley herself either being killed by Trevor, or dying in a crack orgy afterwards.]]
* [[spoiler:Cole Phelps]] of ''VideoGame/LANoire'' is a pretty big one. [[spoiler:A good chunk of the horrible things that happen throughout the game are ultimately a result of his glory-hounding and incompetence during the war. Not only was he directly responsible for driving Hogeboom insane and hardening Courtney Sheldon's heart and indirectly for Kelso's code of silence about their respective misdeeds during and after the war, but the military surplus heist was entirely driven by his former comrades' resentment of Cole for his undeserved honors]]. When [[spoiler:Cole]] realizes what he's responsible for he's ultimately DrivenToSuicide.
* In ''VideoGame/MegaManX'', an archaeologist, Doctor Cain, digs up a hundred-year-old genuinely heroic and kind fully sapient robot, X, who is more advanced than anything known to modern science, to the point that parts can't even be understood. Nevertheless, he tries duplicating the robot, and many other people follow suit, since the resulting replica androids are useful for all sorts of tasks and more intelligent than anything previous. This ultimately leads to at least a half-dozen apocalypses and, ultimately, the extinction of the human species (at least as a unique species). After waking X up and popularizing replica androids, Cain more or less never appears again. It is hinted that he died of old age only shortly before everything starts going to hell with the first ColonyDrop.
* In "The Trouble with Clones" DLC of ''VideoGame/SaintsRowTheThird'' [[spoiler:the Aisha and Tag Brutes have gotten together and it looks like you'll be able to take them away without further trouble... then a National Guard helicopter blows the Aisha Brute up with a missile and the Tag Brute runs away again.]]
* [[spoiler:Boah]] from ''VideoGame/FireEmblemAkaneia'' is this, for [[spoiler:convincing Princess Nyna to marry Prince Hardin, a man whom she cares for but is not ''in'' romantic love with ([[LoveTriangle she loves Camus the Black Knight while Hardin is in love with her]]), for the sake of the Archanea continent.]] The consequences? [[spoiler:Emperor Hardin finds out later and [[HeroicBSOD falls into]] [[DrowningMySorrows drunken depression]], allowing his defenses to become low enough to get BrainwashedAndCrazy when given a certain [[MacGuffin Dragonsphere]] by a disguised villain... and ultimately, to have [[FallenHero Hardin]] ''as the BigBad of the second part of the game''.]] [[spoiler:And Boah pays ''with his own life'', his FamousLastWords to Marth being an apology for the mess he caused while trying to help everyone.]]
* In the ''Videogame/{{Borderlands}}'' series:
** [[BigBad Handsome Jack's]] hunger for the riches of the mysterious Eridian Vaults unwittingly set into motion [[spoiler: an apocalyptic war that would kill billions of people]]. In fact, [[Videogame/BorderlandsThePreSequel Jack was warned about this repeatedly by Colonel Zarpedon and her Lost Legion]], whose mission was to either defend the Vaults or destroy them to prevent them from falling into the hands of humans, but Jack dismissed everything they said and was so blinded by his own greed that he never even considered turning back.
** From ''The Pre-Sequel'', [[spoiler:the [[NiceJobBreakingItHero Watcher's entire plan]] is this]]. Starting off with the Meriff's attempt to shoot Jack while his back is turned after Jack chose to spare him teaches Jack that showing mercy to your enemies is a foolish idea that will inevitably come back to bite you in the ass. This, in addition to [[spoiler:Roland, Lilith, and Moxxi betraying him later in the game]], is what causes Jack to go from someone with genuinely heroic aspirations to a raving megalomaniac who is only the hero in his own mind. Athena even pinpoints the moment that she considers Jack the Hero to have "[[ThatManIsDead died]]", leaving Handsome Jack the BigBad in his place.
* ''Franchise/DragonAge'':
** Varric Tethras once found out about a family of destitute former nobles trying to earn enough coin to buy back their estate. Taking a liking to them and figuring they could help, he decided to let them in on an expedition to the Deep Roads. Through an unlikely chain of events, this eventually leads to a civil war and nearly the ''apocalypse''.
** The Warden Commander of Ferelden (regardless of whether s/he was the Hero who vanquished the Blight or an Orlesian Warden sent as replacement) took the runaway mage Anders under his/her wing, protected him from the Templars who had been pursuing him, thus showing him that Templars could be openly defied and led him to meet the spirit of Justice, events which started Anders' radicalization and led to the eventual start of the Mage-Templar war.
** Hawke, and not just because s/he started the Mage-Templar War. In fact, the entire reason the Breach opened and the world is being threatened in ''Inquisition'' is because [[spoiler:Hawke accidentally released Corypheus from his prison while trying to stop a cult from doing the same in the ''Legacy'' DLC.]]
** It is revealed in ''VideoGame/DragonAgeInquisition'' that the capacity for the Rite of Tranquility to strip mages of their magic [[spoiler:was discovered when a mage attempted to join the Seekers of Truth. Without that, the Seekers would never have started using the Rite on mages, and its use would not have been abused for political, and occasionally [[PrisonRape baser]], purposes, which are among the things that led mages to rebel. All because of one well-meaning mage who thought he found a reliable way to keep mages from becoming [[DemonicPossession possessed]].]]
* The (largely) unseen child killer in the ''Videogame/FiveNightsAtFreddys'' series seems to have no idea that his murders have been the cause of every bad thing seen throughout, as [[spoiler:his victims haunt the animatronics, leading to the death of at least one security guard, the Bite of '87, the closing of Freddy Fazbear's Pizza and, ironically enough, his own death (and subsequent possession of Springtrap)]].
* In ''VideoGame/ResidentEvil2'', [[GasMaskMook an unnamed USS agent]] shoots scientist William Birkin and leaves him for dead while stealing his new virus. Consequently, Birkin injects himself with said virus in an attempt to save his life, and the result is 100,000 deaths and the destruction of an American city at the hands of the United States government [[ItsTheOnlyWayToBeSure by air strike]].
* In the ''VideoGame/{{Mother}}'' franchise, every evil can be traced back to one act: George, the great grandfather of the first game's protagonists, stealing PSI from an alien race. If he didn't do that, Giygas wouldn't have had to attack Earth. If that never happened, Giygas wouldn't have gone insane in the second game as a result and turn into the embodiment of evil. If that never happened, [[spoiler:Porky Minch would never have risen in power. If that never happened, Porky would not have gone into the future in the third game to destroy the world]]. George definitely did not mean for all of this to happen and only appears in the first game, but if he never stole PSI, the events of the entire franchise would never have happened.
* In the ''VideoGame/{{Shantae}}'' series, the unexpected revival of the Pirate Master in ''Shantae and the Pirate's Curse'', turns out to have been unwittingly caused by Risky herself [[spoiler:when she used Shantae's magic to create an evil Shantae clone]] at the end of ''Risky's Revenge''. This act had the unintentional side-effect of creating a new source of Dark Magic [[spoiler:converted from Shantae's Light Magic after Risky used it for evil]], which re-awakened the Scourge of Sequin Land.
* In ''VideoGame/TheSuffering'', Torque causes the apocalypse just by setting foot on [[GeniusLoci Carnate Island]]. He didn't have a choice considering he was being sent to death row at the penitentiary on the island.
* In ''VideoGame/Fallout2'', the protagonist can go back in time and set in motion the events from the previous game by breaking the water chip.
* Later on in ''VideoGame/Persona4'', a politician visits Inaba and interviews a young child about the fog. The problem is twofold- people who appear on TV tend to become targets for kidnapping, even if their faces or names aren't mentioned, and the young child is [[spoiler:none other than Nanako Dojima, the main character's cousin]]- which means that the visit ended up causing one of the darkest parts of the game.
* ''Franchise/FatalFrame'' often has one of these in the past that lead to the disaster that happened.
** In almost all games, a man that made the sacrifice fall for him results in the sacrifice failing and thus hell breaking out.
** Folklorists such as Makabe in the second game or [[spoiler: Asou]] in the fifth game also tend to draw misfortune by messing with the rituals in one way or another.
** Kyozo Kururugi from the fifth game managed to unwittingly destroy almost all protections from the Night Spring. He [[spoiler: killed countless Mikos on the mountain which haunted Ouse, making her unsteady and also killed the protectors of the Holy Fire which is one of the last resorts to calm the the Night Spring]].
* The whole plot of ''VideoGame/TerminalVelocity'' results from Sy Wickens, a janitor from Proxima Seven, getting himself accidentally digitized by S-Max supercomputer. As a result S-Max goes crazy, expands to cover entire planet and starts a crusade against Earth.
* ''VideoGame/TheLegendOfZeldaBreathOfTheWild'' has the King of Hyrule unwittingly kickstarts a series of events that results in Hyrule being in danger and affecting several key characters. [[spoiler: 100 years ago, a fortune teller tells the Royal Family that Calamity Ganon will make a return quite soon. In order to prepare, the King has his people unearth ancient technology that was used to battle Ganon 10,000 years prior. Princess Zelda wants to take part in researching the technology so she can assist with the plan, but her father forbids her from "playing scholar" and that she should focus on training her sealing magic so she can be ready to seal Ganon away and he also assigns Link as Zelda's personal knight. Her father also mentions how the townsfolk are spreading rumors on how she is a failure for not being able to wield the power of the goddess passed down to her. As a result, Zelda becomes unconfident with herself since she feels that she is a failure and Link being around is a reminder of that fact, which also causes her to be unable to awaken her powers. When Ganon attacks, he turns all the Guardians and Divine Beasts against their masters, causing the death of the Champions, the King, and nearly causes Link to die as well, which also breaks Zelda since she feels responsible for not being able to prevent the disaster dominoes. After her powers awaken from the traumatic event, Zelda has Link taken to the Shrine of Resurrection while she faced Ganon alone and has been in a deadlock sealing battle with him ever since. Had the King simply allowed Zelda to do what she wished, not only would her confidence not have been shaky, but she would have likely found a way to awaken her powers on her own.]]
* ''VideoGame/BreathOfFireIII'' has the hooded NPC, Loki. A LazyBum and DirtyCoward to the extreme, he convinces Ryu, Teepo and Rei to raid Mayor [=McNeil's=] manor to give his riches to the town so that the townspeople won't have to work anymore. What Loki didn't realize until too late was that not only is [=McNeil=] as corrupt as they suspected, but he's also got connections to that world's equivalent to TheMafia, who doesn't like being stolen from. [[KnightOfCerebus Balio and Sunder]], CoDragons to TheDon Mikba, were sent to deal with the troublemakers. Loki turns tail, and Ryu and his friends have to fend for themselves, causing the game's infamous PlayerPunch when Balio and Sunder beats the crap out of them, and be left for dead.

[[folder:Visual Novels]]
* ''VisualNovel/SchoolDays'':
** Sekai seduces Makoto because of her own unrequited feelings for him, [[MatchmakerCrush despite actually hooking him up with another girl, Kotonoha.]] This action itself, in the anime continuity, is what leads to Makoto developing a sex addiction, cheating on Sekai with Otome, and then Otome with every other girl in his class, Kotonoha becoming a {{Yandere}}, and well [[DownerEnding the nice boat.]]
** [[spoiler:Otome and Makoto]] might be even worse ones in some routes. It's depending on Makoto pulling one or another action that [[spoiler:Otome will or not tell Makoto's best friend Taisuke that girls like forceful dudes during sex -- which will lead him to rape his crush Kotonoha, under the very stupid belief that the poor girl's barely whispered "no, don't..." are actually a part of the "protest pretend" kink. [[note]]where the passive partner in hentai/ecchi/hard yaoi/etc. media fakes being embarrassment and unwillingness.[[/note]].]]
** Also, [[spoiler: Nanami, Hikari and Otome's GirlPosse]] can become the trope, when [[spoiler: they '''horribly''' bully Kotonoha to [[ShippingTorpedo keep her away from Makoto]] [[ShipperOnDeck and make sure Sekai gets him]].]] This can either lead to [[spoiler: Makoto ''completely cutting Sekai off his life'' before choosing Kotonoha since he thinks she's the one instigating the bullying that Koto has been a victim of [[note]](she's almost surely '''not''', but Makoto is simply too angry to consider that because school bullying is his BerserkButton)[[/note]] ]] or to [[spoiler: Kotonoha [[GoMadFromtheRevelation breaking down so badly]] for said harrassment that ''she murders Sekai in broad daylight''.]] In either way, their support to one girl over the other ''makes things MUCH worse for the one they wanted to "help"''.
* ''VisualNovel/UminekoWhenTheyCry'':
** [[spoiler:Battler Ushiromiya]] of all people, who drives [[spoiler:Sayo Yasuda]] to orchestrate the murders [[spoiler:by unwittingly breaking a promise to take them away from Rokkenjima]]. Battler didn't come back for it because of ''very'' serious family issues (depicted below), but unfortunately, [[spoiler:the already broken Sayo]] took this very, ''very'' badly.
** Furthermore, if that's the case, then [[spoiler: ''Rudolf and Kyrie'']] are also responsible. [[spoiler: Had they not [[ParentWithNewParamour married too soon after the death of Battler's beloved mother]] for the teenage Battler's taste, he would have not broken ties with his paternal family. Therefore, he would've showed up in Rokkenjima sooner and/or more frequently and, as the GuileHero he is, he would've found a way to help poor Sayo deal with their crappy situation, promise or not.]]
** There's also [[spoiler:Natsuhi]], who is largely responsible for [[spoiler:Sayo Yasuda]]'s issues in the first place. [[spoiler:Sayo was pretty much forcibly given to her by Kinzo as a baby to raise after she couldn't give birth to an heir, which [[GoodIsOldFashioned the very traditional Natsuhi]] saw as a reminder of her "failure" as a woman. One day, out of anger and resentment out of having to raise a child that wasn't her own, Natsuhi completely lost it and pushed a servant holding the baby off a cliff. The servant died but the baby survived, though with injuries that damaged their sexual organs, leading to Sayo having major gender/body issues later in life, which would ''not'' exactly help with their increasingly unstable mental state. An alternate continuity shows that, had Natsuhi not snapped the way she did, Sayo would grow into the [[TheAce far more stable]] [[AlternateSelf Lion Ushiromiya]].]]
* There are two of them in ''VisualNovel/HigurashiWhenTheyCry'':
** Ooishi, whose InspectorJavert tendencies provoke the events of the Spirited Away and Atonement chapters.
** Oryou, whose actions and policies are directly responsible for Cotton Drifting and Eye Opening or indirectly responsible for many of the other chapters via the treatment of the Hojo siblings and in provoking Ooishi above.
* ''Franchise/AceAttorney'':
** The games have one (although it's more attributed to the series being a LongRunner more than anything): [[spoiler:Tsukasa Oyashiki]] is indirectly responsible for the DL-6 incident, thanks to [[spoiler:inadvertently hiding the IS-7 victim's body. This was due to the fact that she was trying to prevent the destruction of some ice statues made by the victim, and didn't even know the killer hid the body there. Because of that, she's responsible for the forgery of evidence and Manfred von Karma's black spot on his perfect record]]. Even worse, the DL-6 Incident led to [[spoiler:the Feys losing their reputation, causing Morgan's husband to leave her and Dahlia to grow up to become a serial killer.]] Poor [[spoiler:Tsukasa]]'s got a ''lot'' of blood on [[spoiler:her]] hands.
** Jake Marshall is one for Case 1-5. He approaches Bruce Goodman, asking him to re-open SL-9, but Goodman refuses. Marshall then steals Goodman's ID to retrieve the evidence himself, prompting Goodman to have to enter the evidence room with [[spoiler:Police Chief Damon Gant]] in order to complete the transferal. Not realizing he was with Neil Marshall's true killer, Goodman changes his mind and suggests reopening the case, [[spoiler:and is killed on the spot before being transported to the underground parking lot]]. Marshall thus, either by stealing Goodman's ID or planting a seed of doubt in Goodman, indirectly caused Goodman's death.
* During Hanako's route in the VisualNovel ''VisualNovel/KatawaShoujo'' [[spoiler:Misha]] decides to teasingly question her and Hisao about their relationship. As a result of this queston [[spoiler:Hisao is forced into a situation where he had to tell Hanako about the suprise birthday party that he and Lily were planning for her. This just happens to cause [[FragileFlower Hanako]] to have [[AngstComa a SEVERE panic attack]].]] In [[spoiler:Misha]]'s defense she truly didn't know that [[spoiler:[[BirthdayHater Hanako's birthday]] was a {{trigger}} for her]], and she's genuinely sorry for the consequences.
* Ryousuke Katayama of ''VisualNovel/CorpseParty'' is a weird example, in that it's not exactly his fault. [[spoiler:In Tenjin Elementary School, he loses his leg in a trap and bleeds to death.]] His friend Ohkawa, however, [[spoiler:insists that he's still alive and needs to get to a hospital. In an attempt to "help" him realize the truth, Kizami pushes his body down the stairs]]. [[FreakOut This works about as well as you'd expect]]. Ohkawa [[spoiler:calls Kizami a murderer, which causes Kizami to have an "epiphany": It doesn't matter whether it's the school that kills you or him]].
* In ''VisualNovel/ZeroTimeDilemma'' Zero mentions a story how a ''snail'' caused 6 deaths by just being where he was. A woman [[spoiler: heavily hinted to be Eric's mother]] used different way than usual beacuse a snail was on the usual one. This caused her to meet a SerialKiller, [[spoiler: who turns out to be Mira]], and get killed. An innocent man [[spoiler: later revealed to be Akane's father]] was caught and sentenced to death, which lead his wife to suicide. Man was going to catch a taxi but he didn't, and taxi driver caught a surgeon going to operate a kid. Taxi had an accident and both driver and surgeon died. Since the kid never recieved his surgery, he died as well. [[ArcWords Life is simply unfair]]

[[folder:Web Animation]]
* In ''Machinima/RedVsBlue'':
** It's revealed in season 10 that [[spoiler:Carolina]]'s pride was responsible for nearly everything bad that happened to the Freelancers--[[spoiler:her original AI was Sigma, but she gave him up to Maine. Sigma and Maine went on to become the Meta and kill several other Freelancers. When she finally did get an AI, she took ''two'': the ones that were originally meant for Wash and South. South's jealousy due to her brother North getting an AI and her not led to South leaving North to die and shooting Wash in the back, and her own death at Wash's hands later. Wash, on the other hand, did get an AI... Epsilon. Which led to him going insane and plotting to take down the Director of Project Freelancer for his crimes.]] All because of pride.
** There's [[spoiler:the Director's obsession with his dead love, Allison. When the Alpha AI, copied from the Director's mind, was created, the Beta AI (based on the Director's memories of Allison) naturally fragmented from it. This inspired the Director to torture the Alpha into making more fragments, the ones mentioned above, to figure out a way to "get her right".]]
** There is also [[spoiler:the Sleeveless Insurrectionist Soldier, who shot Agent Maine in the throat several times, rendering him mute. This gave Carolina an excuse to give her A.I. Sigma away so that Maine could have an alternate way to speak. This contributed into forever turning him into the Meta.]]
** Season 14 ultimately reveals that [[spoiler:everything happened because Agent Florida tripped over a wire and broke it. Originally, had something happened to him, other Freelancers were to show up and take his place, starting with Agent California. However, by damaging the wire, the list of Freelancers were replaced by five other names, starting with Caboose. Thus, because of a damaged wire, Agent Florida would kick off a series of events that would lead to the destruction of the Freelancer Project.]]
* In ''WebAnimation/DeathBattle'', [[WesternAnimation/HeManAndTheMastersOfTheUniverse1983 He-Man]] ended up as this during his fight against [[WesternAnimation/ThunderCats Lion-O]]. He just wanted to fend off Lion-O, but in doing so, [[spoiler:he crushed the Eye of Thundera, which kept the Thunderan race alive.]]
* ''WebAnimation/LlamasWithHats'': In episode 7, Paul [[spoiler:severs all ties with the series' AxCrazy VillainProtagonist Carl]], as any sane person would and should. However, it turns out that [[spoiler:Paul's friendship was the only thing keeping Carl a little bit sane (a very, ''very'' little bit), and without Paul around Carl ends up destroying all life on Earth.]]

[[folder:Web Comics]]
* In ''Webcomic/KidRadd'', two Moderators are given a large sum of money in order to hire an assassin to kill Radd, as Captain QB can't be directly implicated in illegal activities and needs to use a proxy. They reason that it can't be hard to kill someone in jail (as Radd is being imprisoned for illegally entering other games), and hire Kobayashi the discount ninja so that they can pocket the rest of the money. Radd survives the assassination attempt and Kobayashi becomes a recurring character who later meets up with Gnarl and, while training together, stumbles upon [[spoiler:Chimera Point, the keystone to Crystal's plans, which eventually results in ''her'' finding it too]].
* In the ComicBook/ChickTract "Fatal Decision", Brutus, an orderly on the brink of being fired for rudeness to patients, makes hints that John shouldn't trust Dr. Bowers, leading to John destroying the vaccine and dying of his disease.
** The devils often invoke this trope, choosing someone who has an incidental relationship to the person whose soul they want to claim. In "The Assignment" they succeed in convincing Charles Bishop's subordinate's wife to badger him out of witnessing to his boss. They try to distract Cathy with a boy, only for it to fail when he proves to be a JerkAss, and try to have the previously mentioned subordinate call Bishop with a sales proposition, only for the angels to thwart this attempt twice. Charles ultimately dies in his sins, making the first example a successful one.
* In ''Webcomic/KevinAndKell'', [[Webcomic/GeneralProtectionFault Nick and Ki's]] [[{{Crossover}} arrival in Domain]] by way of interdimensional travel disrupts the balance between the animal- and human-dominated worlds to the point at which the other two humans living on the animal side [[spoiler:Lindesfarne and Danielle]] are forced to leave lest the world suffer instinct loss. [[spoiler:Luckily, Catherine and Nigel do it instead]].
* [[KnightTemplar Miko Miyazaki]] from ''Webcomic/TheOrderOfTheStick'', having already [[DePower lost her Paladin abilities]] through the unwarranted execution of of Lord Shojo, ends up destroying the [[MacGuffin Sapphire Gate]], having once again misinterpreted what the gods wanted of her. Had she not been so hasty in doing this, the ghost of [[PrecursorHeroes Soon Kim]] could have permanently ended the threat of [[BigBad Xykon]] and [[DragonWithAnAgenda Redcloak]], who, themselves, were aiming for the gate, anyway.
* Several characters in ''Webcomic/{{minus}}'' take actions that, unbeknownst to them, lead to TheEndOfTheWorldAsWeKnowIt. First, a mysterious man pretty much "breaks" [[RealityWarper minus]] by stuffing her into a briefcase. She is freed, but becomes a CloudCuckooLander. In an attempt to cure her, the green-haired girl throws a rock at minus's head, causing her [[spoiler:[[LiterallyShatteredLives to shatter]]]]. Because she is now [[spoiler:a ghost]], minus starts to spend more time with her ghost friends than her live ones. Which leads to the biggest example of this trope in the comic: the red-haired ghost asks minus to bring her back to life, because she has some UnfinishedBusiness with certain humans that the readers don't get to see. minus agrees. Unfortunately, once the other ghosts find out, they demand that minus revive them too. She does, [[spoiler:only for the sheer influx of bodies on Earth to suffocate every living thing on the planet, including those who were just revived]]. [[SpaceWhaleAesop And that is why you should never ask anything of an omnipotent being, ever.]]
* Virtually everyone in ''Webcomic/{{Homestuck}}''; the ''single'' good character who doesn't manage this is Nepeta[[note]]largely because she's never shown actually ''doing'' much of anything; the one time she tries to do something significant she's hopelessly outclassed and dies pointlessly and almost immediately[[/note]].
** Tavros deserves special mention. At one point he attempts to save a young Jade from accidentally shooting herself by taking psychic control of her dog, Becquerel, and deflecting the shot at her grandfather (whom he believed was a hostile intruder), killing him. He then points out that Becquerel would have saved her even if he hadn't done anything (in a way that would not have killed Grandpa Harley) and that he only interfered so he could feel a little better about himself. Even when she points out that killing her grandfather was ''not'' appreciated, he still thinks he made the right choice.
* In ''Webcomic/{{Freefall}}'', Florence has suspicions that Maxwell Post might be this when she learns that he is the spiritual advisor to the [[AIIsACrapshoot sapient robot]] population. [[SubvertedTrope So far, his efforts have been among the least of her worries.]]
* One ''Webcomic/ElGoonishShive'' storyline featured a rampaging boar which was enchanted to grow to an enormous size. Said enchantment is heavily implied to have come from [[spoiler:Rhoda]], who was unwittingly given a [[PowerTattoo magic mark]] and unknowingly used it on the boar while in a state of panic.
* In ''Webcomic/NobodyScores'' this is frequently the role of [[Main/{{CloudCuckoolander}} Jane Doe]]. [[http://nobodyscores.loosenutstudio.com/index.php?id=488 This]] for example.

[[folder:Web Original]]
* ''Wiki/SCPFoundation'', Characters/SCPFoundationSCPs1000AndBeyond, [[http://www.scp-wiki.net/scp-1867 SCP-1867 ("A Gentleman")]]. If the accounts are correct, Lord Blackwood may have just been the one that [[spoiler: inspired SCP-319's maker to try and travel to another universe, and given him the means to attempt it]]. A short read of that particular file lets us know that attempt essentially ''doomed this universe''.
* Trouble in ''Roleplay/DinoAttackRPG'', being a mutant lizard who was adopted and trained by a member of the team trying to eradicate his kind, was the first to spark the tension between realist and idealist members of the team. Technically speaking he is responsible both for the campaigns by both Kotua ''and'' Cam O'Cozy, both of whom tried to commit genocide against idealist agents.
* In ''Literature/{{Worm}}'', the Undersider's local [[TheSmartGuy Smart Girl]], Tattletale, normally isn't this, but a character flaw of hers is to start throwing everything her SherlockScan superpower picks up everywhere when she panics. This doesn't really hurt anyone...with the rather glaring exception of [[spoiler:cluing [[TheMedic Panacea]] into her family history...which sets off the [[DysfunctionJunction time bomb]] of issues that is her adopted family, and ends with Panacea's incarceration and her sister becoming a [[AndIMustScream miserable pile of immobile flesh]].]]
* ''WebVideo/DontHugMeImScared'':
** [[spoiler:Red Guy]] is heavily implied to be this in the fifth episode. At the beginning of the episode, Duck Guy and Yellow Guy note that something's "missing", unaware that it's [[spoiler:their friend Red Guy.]] Near the beginning of the episode, a phone rings, and when Duck Guy answers, he's suddenly in an operating room, watching himself on the television, with a mysterious voice saying "you have to know right from wrong". This seems to lead him to realize that the lesson would go wrong somehow and try to escape, [[spoiler:for which he is EatenAlive.]] The end credits imply that [[spoiler:the call was made by Red Guy, who somehow escaped from the lessons and was trying to help his friends escape, and hearing Red Guy's voice was what made Duck Guy realize what was going on. If it weren't for Red Guy, Duck Guy would probably still be a live, and Yellow Guy wouldn't be completely alone.]]
** The sixth video takes this further by implying that [[spoiler:Red Guy is [[GainaxEnding somehow]] inadvertently causing the GroundhogDayLoop the puppets are trapped in.]]
* ''Series/{{Noob}}'':
** In late Season 4, Kary commits the InnocentlyInsensitive act of [[spoiler:choosing to check out an in-game event over finishing her (in-game) wedding to Arthéon, who was taking it much more serously than she was.]] Arthéon was so furious that he went on a RoaringRampageOfRevenge. Even after he calmed down, he still had a much more cynical view of everyone and everything he knew than before. This became a really bad thing [[spoiler:because Arthéon eventually got a job that enabled him to impact the game's plot and the story has reached a point where he will be responsible for the game world's destruction unless his former guildmates stop him]].
** In late Season 5, Roxana keeps Saphir from doing a quest that impacts the game story and may have the side a effect of making Saphir's guild outrank Roxana's once it's done. The reason the quest could have been singlehandedly enough to significantly uprank Saphir's guild? It would bring a big blow to the BigBad if accomplished, help make him stronger if failed.

[[folder:Western Animation]]
* A strange example of a fictional character ending up being one for the real-life events. ''WesternAnimation/TheRenAndStimpyShow'' had the minor character George Liquor getting brutally beaten up by Ren in the episode "Man's Best Friend". Said scene was later one of the reasons for creator Creator/JohnKricfalusi's firing.
* ''WesternAnimation/AvatarTheLastAirbender'': The Earth King informed Azula (disguised as a Kyoshi Warrior) of the invasion of the Fire Nation. Cue next season where the invasion force finds all royalty in hiding, and the invasion ends in failure with almost all of them captured. Zuko hoped this would lead to his father re-thinking his strategy with the war. Unfortunately, it did, but it led to Ozai plotting genocide on the Earth Kingdom.
** During a war council, Zuko is asked how the people of the Earth Kingdom would react to occupation. He honestly replies that as long as they had their pride, they would never give into the Fire Nation. His statement led to Ozai plotting genocide on the Earth Kingdom.

* ''WesternAnimation/AdventureTime'':
** The Ice King continually interferes with Finn's attempt to prevent [[VileVillainSaccharineShow the Lich]] from reaching the Well of Power and regaining his full power. As a result the Lich, having regained his full power by the time Finn and Jake finally reach him, [[NoHoldsBarredBeatdown ends up jobbing Finn]] and destroying the Gauntlet, the one weapon that can hurt him, forcing Finn to find an alternative. Then the Ice King accidentally drops Bubblegum into the Well, which melts her and allows the Lich to possess her. After being frozen with help from the Ice King, she shatters, requiring medical attention to be put back together. Part of Bubblegum is missing though, causing her to come back as a 13-year old, which later results in [[RoyalBrat Earl of Lemongrab]] assuming the throne, if only for an episode.
*** The snail was responsible for the Lich breaking free in the first place. He just happened to have crawled into Finn's backpack right before Princess Bubblegum took Finn and Jake to the location of [[CrystalPrison the Lich's imprisonment]]. As soon as he crawled out, the snail, having no psychic protection, was mind controlled by the Lich into freeing him and setting the above chain of events into place, not to mention the ongoing threat of the Lich when [[spoiler:the Lich possesses the snail directly]].
** If it weren't for an unnamed Scandinavian dock worker selling an old crown to an antiquarian [[spoiler:by the name of Simon Petrikov]], the Ice King would never have existed. However, if that happened then [[spoiler:Marceline]] would have most likely died in the [[AfterTheEnd post-apocalyptic wasteland]], so it isn't all bad.
** In the AlternateUniverse [[FanNickname "Farmworld"]], the Destiny Gang terrorising Finn's village and his family leads to ''him'' wearing the Ice King's crown, which in turn leads to the release of the Lich and the world being inflicted with ''another'' apocalypse.
* In the one episode of ''WesternAnimation/ComboNinos'' where [[NotMeThisTime neither Diadoro nor Gomez]] had released any Divinos, Principal Bronka accidentally released a Family of snake-like Divinos.
* In the ''WesternAnimation/FostersHomeForImaginaryFriends'' special WesternAnimation/DestinationImagination, Herriman {{inter|ruptedCooldownHug}}feres with a resolution between the Face and the rest of the main characters, Frankie included, by scolding him, causing him to go berserk. Unlike most other examples of this trope, he immediately comes to regret this.
* Everything that went wrong in the ''WesternAnimation/{{Kissyfur}}'' episode "The Birds And The Bears", from the cubs taking Gus' paddlecab for a spin which eventually leads them through dangerous rapids to the gators taking control of the paddlecab and using it to capture the cubs, all happened thanks to [[OneEpisodeWonder Donna's]] rebellious behavior. She even [[LaserGuidedKarma gets called out for it]] when she and some of the other cubs are captured by the gators.
--> '''[[JerkAss Lenny]]:''' [[JerkassHasAPoint It was]] ''[[JerkassHasAPoint your]]'' [[JerkassHasAPoint dumb idea to fool with the paddlecab, Donna!]]\\
'''Duane:''' Yeah, it definitely wasn't a cool thing to do!\\
'''[[TheEeyore Stuckey]]:''' Not cool at all!
* Many a ''{{WesternAnimation/Rugrats}}'' episode's plot gets kicked off by the babies misunderstanding something they hear from the adults:
** "The Old Country" has Tommy overhearing Stu talk about trying to "keep out the elements" while staying in a cabin in the woods, and misunderstanding him to think that elephants are going to crush them all.
** "The Legend of Satchmo" has Grandpa spooking the babies with a story about Sasquatch, prompting them to run off and get lost in the garden.
** "Reptar on Ice" has Angelica talking about how the dinosaurs went extinct, prompting the babies to think that [[HesJustHiding Reptar must be in hiding]] and so they wander off to find him at the titular ice show.
** "The Dog Broomer" has Tommy again mishearing 'dog groomer' as 'dog broomer' and is convinced that the woman hired to groom Spike is going to kidnap him - causing all sorts of trouble for her.
** "Dummi Bear Dinner Disaster" has the babies scheming to ruin a dinner party when Susie fears she might have to move if it goes well (her father is just having a business colleague over").
** "When Wishes Come True" has Drew bringing a statue of Angelica to the house, with the babies fearing that Angelica has somehow been TakenForGranite. Of course the expensive statue ends up broken in their attempts to revive her.
* Homer from ''WesternAnimation/TheSimpsons'' does this at least once or twice a season. He's even responsible for the death of Maude Flanders; Homer tells a group of bimbos to aim their [[ItMakesSenseInContext 'Free t-shirt' bazookas]] at him, only to duck at the last possible second as he grabs something off the ground. The barrage of t-shirts knocks Maude over the edge of the stadium to her death in front of her ''husband and two young children''.
-->'''Homer:''' I'm the one whose antics drove her out of her seat. I'm the one who provoked the lethal barrage of t-shirts. [[RuleOfThree I'm the one]] who parked in the ambulance zone, preventing any possible resuscitation.
* In the season 6 premier episode for ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', Flurry Heart destroys the Crystal Heart, the magical artifact that protects the Crystal Empire by keeping out the arctic climate of the rest of the region. This results in a massive blizzard that threatens to destroy the entire kingdom and either drive off or ''kill'' the inhabitants. The unwitting part is because she's a ''baby [[WingedUnicorn alicorn]]''; she didn't intend to destroy it, she didn't even have the cognizance to realize what was going on. Fortunately, the Crystal Heart gets repaired and in the process seems to have helped brought her own power under control.
* The third ''WesternAnimation/RobotChicken'' ''Franchise/StarWars'' special has an unnamed man suggest that Palpatine go into politics, which of course eventually leads to him becoming Emperor, the galactic war, the forming of the Empire, and the destuction of the Jedi. Said man is seen thirty years later realizing that it was all his fault and preparing to commit suicide...at least until ''Series/WheelOfFortune'' comes on.
* ''WesternAnimation/{{Kaeloo}}'': Stumpy is one in the episode "Let's Play the Quest for the Wholly Gruel". [[spoiler: He finds the titular Wholly Gruel, a magic crayon which can make anything it draws real, and uses it to doodle all over some hieroglyphics in a cave depicting characters who resemble him and his friends. He draws a meteorite about to strike them, and his real friends, meanwhile, almost get hit by an actual meteorite.]]

[[folder:Real Life]]
* Creator/SamuelTaylorColeridge had a vivid dream, got up and started writing it down as the epic poem ''Kubla Khan'', [[http://sydneypadua.com/2dgoggles/the-person-from-porlock/ but then there was a knock at the door,]] and a man from the nearby town of Porlock kept him talking just long enough to forget all about the dream and he never finished it. The [[http://en.wikipedia.org/wiki/Person_from_Porlock Person from Porlock]] is now literary shorthand for an unwanted visitor.
** Though some have theorized that Coleridge never intended to finish the poem (or that it was finished already), and he made up the story of the visitor just to mess with people. It doesn't help that Coleridge was a heavy opiate user, and the "dream" could have been something more of a "drug-induced vision," and the man from Porlock may or may not have actually been there. (Cue images of a poet standing on his doorstep talking to nobody while hazy visions of Kublai Khan's utopia dissipate into the aether.)
* UsefulNotes/ChristopherColumbus's voyages opened up the Americas to the Old World, bringing over disease which wiped out 90% of the Native Americans.
* Andy Dick. At a 1997 Christmas party, he reintroduced Brynn Omdahl, wife of Creator/PhilHartman, to cocaine, leading to his death. Which led to Andy Dick [[KickTheDog making some tasteless jokes about his role in Hartman's death,]] which resulted in Hartman's friend Jon Lovitz kicking his ass. It appears that Dick lives up to his name.
* Floyd Wells. He told fellow cons Perry Smith and Richard Hickock that a farmer he worked for named Herb Clutter kept a safe hidden with plenty of cash inside. As it turned out, there was no safe. It was this false info that led Smith and Hickock to massacre Mr. Clutter and his family, the basis for Creator/TrumanCapote's ''Literature/InColdBlood''.
* A rare inversion in [[http://en.wikipedia.org/wiki/Stanislav_Petrov Stanislav Petrov]]. While monitoring a satellite for the Soviet early warning system of a nuclear attack, he received a report of five inbound [=ICBMs=]. He decided it didn't make sense for a US first strike to be composed of only five nukes, he logged it as a technical error and overrode the command to launch a massive retaliation strike. Had he not been so cautious, WorldWarIII surely would have erupted.
* The failure of the Jay Leno Show on primetime had this effect on Creator/ConanOBrien's tenure as host of TheTonightShow, as it damaged local 11pm newscast ratings, as well as Conan himself, leading NBC to move Jay and his show back to his old 11:35 spot, and pushing Conan just past midnight. Conan, [[JudgmentOfSolomon not wanting to tarnish the legacy of the Tonight Show]], wanted no part of the agreement, and was subsequently evicted from the show, with Jay back as host.
* Senator Stephen Douglas, the man responsible for the Kansas-Nebraska Act. Originally, his intentions had simply been to get a railroad to California built, which would start in Chicago, Illinois (his home state). To do this, he proposed splitting the remaining unorganized chunk of the Louisiana Territory into the territories of Kansas and Nebraska. Pro-slavery Southerners slipped in a part saying that the legality of slavery in each territory would be decided by the voters there. But then pro-slavery advocates from Missouri flooded into Kansas to support slavery, resulting in "Bleeding Kansas", the prequel to UsefulNotes/TheAmericanCivilWar. Douglas himself has been branded pro-slavery for many years afterward following the fallout, with historians often leaving out that it was the South that suggested the decision of slavery by popular sovereignty and that Douglas himself simply wanted to build a railroad to California, obviously having no idea that the first planned transcontinental railroad would cause [[UsefulNotes/TheAmericanCivilWar the biggest schism ever to hit the United States]] over completely unrelated circumstances.
* In 2007, Creator/AdultSwim launched a guerrilla marketing campaign for the ''WesternAnimation/AquaTeenHungerForce'' [[TheMovie movie]] featuring battery-powered LED placards resembling the Mooninite characters being placed in numerous places around the US. However in Boston, police officials mistakenly thought that the [=LEDs=] were bombs, and treated the whole event as such. This event would turn out to known as the [[http://en.wikipedia.org/wiki/2007_Boston_bomb_scare Boston Bomb Scare]], which lead to legal implications being placed on Turner Broadcasting and their contractors, the internet to make mock [[MemeticMutation "Never Forget" memes]], and forced then-current Creator/CartoonNetwork head Jim Samples to step down. It wouldn’t be long after until fans began to realize that Creator/CartoonNetwork would not be the same since the incident. Not because of any legal incidents, but because Sample’s replacement, Stuart Snyder, became the instigator of the channel’s infamous NetworkDecay, and an increase in Live action, and sitcom style shows.
* Franz von Papen, ex-Chancellor of the Weimar Republic, who in 1933 convinced President Hindenburg to make UsefulNotes/AdolfHitler chancellor in order to save his own political hide. By this point, the Nazis (forced by previous chancellors to fight repeated elections which sapped their funds) were rapidly losing support and were scraping the bottom of their piggy bank.
* Marinus van der Lubbe, the guy who started the Reichstag fire. He was a raving madman who was quickly captured that same night. It gave the Nazis the perfect opportunity to seize power, as the aforementioned repeated elections would eventually end in a loss of NSDAP seats.
* In the mid-'80s bribery scandal linked to R. Budd Dwyer (the inspiration behind "Hey Man, Nice Shot" by Music/{{Filter}}), William Smith, an attorney linked to the case, gave dubious testimony in order to accept a plea bargain, which made a guilty verdict for the former practically inevitable. As a result, Dwyer himself [[AteHisGun publicly committed suicide]] the day before the sentencing was to have taken place.
* In the night of April 14, 1912 Jack Phillips, radio operator of the ''RMS Titanic'', received a message alerting of an ice field ahead from the radio operator of the ''SS Californian'', Cyril Evans. The message interrupted an information directed to a first class passenger from Cape Race, Newfoundland, and Phillips radioed "Shut up, shut up! I am busy; I am working Cape Race!" back to Evans. Annoyed, Evans turned off the radio and went to sleep... ten minutes before the ''Titanic'' struck an iceberg. This prevented the ''Californian'' (who was the closest ship to the ''Titanic'') from hearing the ''Titanic'''s repeated distress calls and rescuing her passage before the ship went down.
* David Blair was originally slated to be Second Officer of the ''Titanic'' during her maiden voyage. However, in the last moment White Star reassigned the more experienced Henry Wilde, Chief Officer of the ''Olympic'' (at the time in drydock) to the ''Titanic'', and the knock-off effect was Blair being given another post out of the ship. By accident, Blair left with a key from the ''Titanic'', that turned out to be the only key to a safe in the Crow's Nest keeping the lookouts' binoculars. Without binoculars, the lookouts failed to see the iceberg in time.
* Jamie Gorelick, during her tenure as Deputy US Attorney General, was responsible for strengthening the restrictions on information sharing between domestic and foreign intelligence services. [[RightHandVersusLeftHand The lack of coordination]] this caused lead directly to the US government's failure to prevent the September 11th attacks, despite ample evidence of the plot, up to and including one of the terrorists being (briefly) taken into custody not long before it happened.
* Creator/SethRogen has become this with regards to the now-notorious consequences from ''Film/TheInterview'' and the cost it left Sony with. He knew that the film would piss off North Korea, and went ahead with it, presumably figuring that the DPRK would once again fail to follow up on its threats. However, he probably couldn't have seen his move as coming at the cost of the financial stability of the company he was working for, or The Guardians of Peace outright threatening terrorist attacks in theatres where it was due to play.
* On April 20, 2007, Davon Boddie was arrested for pot dealing outside of the Royal Suite nightclub in Roanoke, Virginia. Boddie was the cousin of [[UsefulNotes/AmericanFootball Atlanta Falcons quarterback]] Michael Vick, and gave Vick's home address as his own. Five days later, police searched the home and discovered a massive [[http://en.wikipedia.org/wiki/Bad_Newz_Kennels_dog_fighting_investigation dog-fighting ring]], leading to the arrest and conviction of Vick and four others.
* Gavrilo Princip and his co-conspirators in the assassination of Archduke Franz Ferdinand. All they wanted was a re-arrangement of some political borders in one part of the Balkans. What they got was a world-spanning war which was the deadliest in history, which led to the fall of the European colonial powers and the rise of communism, ''another'' world-spanning war 20 years later which became the new most deadliest war in history as a result of the mess the previous one left, and a subsequent cold war due to the results of the previous war that kept the world on the brink of destruction for fifty years. [[ArsonMurderAndJaywalking Oh, and that Balkan situation never was properly sorted out.]]
** To take it a step further, Ferdinand's driver, who was supposed to be taking him visit some people in the hospital, got lost, tried to reverse, and stalled the car almost exactly where Princip happened to be at that exact moment. Probably the most consequential wrong turn in human history.
* The TGWTG WebVideo/ToBoldlyFlee movie had a lot of effort and a lot of time put into it, but it was also a big TroubledProduction with many producers having bad memories of filming. As shown in the behind the scenes feature, things were apparently running smoothly until Rob Walker had the bright idea to lie about running fifteen minutes late. You can see Doug's face fall when he's told this, and according to [[WebVideo/TheNostalgiaChick Lindsay]] and [[WebVideo/ToddInTheShadows Todd]], that's when things started to break down.
* Best Buy's acquisition of Musicland in 2001 and their subsequent gross negligence, including making it ''[[EpicFail hemorrhage $80 million]]'' '''''[[EpicFail in one year]]''''' before selling it the following year, ultimately drove it to bankrupcy, leading to a mass closing of stores before being brought by Trans World Entertainment (owner of competitor FYE) in 2006. The mass closing of stores caused unsold stock to be taken back to the warehouses. While this has affected all home video companies, anime companies (who were 100% reliant on home video sales due to the lack of digital distribution rights at the time because [[ExecutiveMeddling the Japanese licensors refused to give them those rights]] as [[InsaneTrollLogic they equated legal digital distribution with piracy]]) were particularly severely affected, leading to the crash of the North American anime industry by the end of the 2000s, including the closures of Creator/{{ADV Films}}, Creator/{{Geneon}} and Creator/CentralParkMedia, and the downsizing and eventual closure of Creator/BandaiEntertainment. On the general side, the mass closing of the stores led to a decline of home video sales, which was further exacerbated by the growing ubiquity of streaming services such as Hulu and Netflix.
* [[WesternTerrorists Dylann Storm Roof]], a white supremacist who took pictures of himself with Confederate memorabilia some time prior, shot up a church in Charleston with the hopes of dividing the nation. Not only did he [[EpicFail fail spectacularly]], he also caused collateral damage when his actions, which turned the general public (even in the South) against the Confederate flag, managed to TARFU ''Series/TheDukesOfHazzard''[='=]s reputation, if not outright FUBAR it.
* The PunicWars was started by a band of mercenaries called the Mamertines who took over the city of Messana, and the Romans and the Carthaginians turn their attention away from them and then against each other over control of Sicily. What followed was years of bloody wars between the two empires, which finally ended with the destruction of Carthage.
* Faida Hamdi was a Tunisian government worker. In late 2010, she had a confrontation with a street vendor and confiscated the vendor's cart. The vendor set himself in fire as a protest in front of a government building. His death [[UsefulNotes/TheArabSpring led to protests across the Middle East]] and the protests soon turned to devastating wars that would go on to shake the whole world. Today, Hamdi [[http://www.telegraph.co.uk/news/worldnews/africaandindianocean/tunisia/12054657/I-started-the-Arab-Spring.-Now-death-is-everywhere-and-extremism-blooming.html wonders]] WhatCouldHaveBeen if she did not have that initial confrontation.
* Michael Dukakis authorized weekend passes for prisoners while Governor of Massachusetts. One recipient of these weekend passes, Willie Horton, kidnapped, murdered, and raped one weekend. This ended up costing Dukakis the 1988 Presidential election and made politicians wary of being honest about their stances on crime, which led to the sudden toughening of criminal laws under Bill Clinton.
* Portuguese missionaries who threatened to conquer Japan through the forced spread of Christianity were directly responsible for centuries of de jure xenophobia in the country, which only started to be loosened (key word: started, only in 2017 did discrimination against foreigners living in the country start to significantly fade in earnest) when Matthew Perry opened trade routes between the United States and Japan in the middle of the 19th century.