You'd think the opposite of Gone Horribly Wrong would be a good thing, right?
You'd be wrong. Horribly wrong.
Rather than have something unexpected happen that sabotages the program, the researchers have everything proceed in an orderly fashion. The results are everything they hoped for; better, in fact. Unfortunately, they've succeeded too well, and it's this success that dooms them. Either it turns out to be too intense, too powerful, or they didn't fully consider the consequences of what they wanted to do.
The results are either a runaway chain reaction that threatens to destroy the facility/city/world/universe, a weapon that not only annihilates its target but has high (or total) collateral damage, or a Psycho Prototype that obeys orders only too well. Other times, they find out the result was something they shouldn't have attempted in the first place. The Potential Applications were so exclusively in the evil/destructive side that the project had no possible use but to destroy.
Things that have Gone Horribly Right might not be immediately apparent. The researchers may create and market an entire product line based on their Super Prototype that only later turns on them, or over-performs their duty like, say, a genetically engineered plant that has a high CO2 consumption out-competing every other plant on the planet and causing massive fires to keep feeding. Usually this is paired with a Fantastic Aesop that (heavily) implies the intended use or goal of the research is to blame.
This trope may be most succinctly captured in Jurassic Park, and directly spelled out in Aesop fashion, with Ian Malcolm's line "You spent so much time wondering whether or not you could, that you didn't stop to think whether you should."
Most examples of A.I. Is a Crapshoot are this (and see also The Computer Is Your Friend). A Sub-Trope of Literal Genie, putting it in the scientific category as opposed to Be Careful What You Wish For, which is when what the character wanted falls in their lap through coincidence or magic rather than their own planning and hard work. Compare Springtime for Hitler, What Could Possibly Go Wrong?, Nice Job Breaking It, Hero or Hoist by His Own Petard. Didn't Think This Through often follows the realization of this trope.
In episode 15 and 16 of Season 2's Ah! My Goddess, Marller manages to separate Urd's evil half from her good half and transport it to an artificial body that looks exactly like Urd. Seems to go well for Marller, until evil Urd starts to suffer a Super Power Meltdown due to her body being unable to handle the magic being used. In addition, the evil half seems to want to do things even Marller hadn't thought of, or wanted to do, such as taking over the world, rather than simply kicking the goddesses out of Earth.
AKIRA: The experiment in this movie was just a really, really bad idea, as was demonstrated twice over.
Saikano. The goal was to make an unstoppable killing machine. The problem came when it became a bit too unstoppable. Eventually, Chise begins to find the whole war pointless. It's all the same, just with different uniforms. If they're all going to die anyway, why should she pick and choose who she kills? At that point, she just starts nuking major cities. This being Saikano, it goes From Bad to Worse.
Interestingly, one of the main heroines of the series, and the one who personally defeats the Big Bad at that, had years earlier been created by him. As was the case with his own creators, he found that overachieving has its perils.
In Uchuu Senkan Yamato, the heroes first use their Wave Motion Gun to destroy an enemy base on Jupiter's Floating Continent. To their shock, they find out just how powerful the gun is when the resultant blast destroys the entire continent and almost destroys their ship. From then on, they're far more judicious about when to use the thing.
A similar type one happens in Robotech/Macross when the SDF-1 is programmed to do a space fold to the moon. It is floating above Macross Island when it warps out. Since the crew didn't understand entirely how the space fold system worked, there were...complications. The warp bubble was large enough to warp out the SDF-1...and the entire island, including two ships docked in Macross Bay! Fortunately, the island's denizens were in airtight emergency bunkers, so no one (that we know of) died. Also, they ended up on the far side of Mars Pluto! However, the people on board the Daedalus and Prometheus weren't so lucky. The Daedalus was an amphibious assault vehicle (not submarine), and the Prometheus was a semi-submersible aircraft carrier. According to the show, neither ship could be hailed and were immediately assumed to have all hands lost due to the neither being designed for space. Roleplaying supplemental information states that crew of the Prometheus survived because of the semi-submersible construction.
In The Shadow Chronicles, Netron-S Missiles turns out to be this. Had even a single missile detonated on Earth, it would turn Earth into a black hole, obliterating all the Invids and humans still there, AND obliterate the entire RDF fleet.
The back story, the "scenarios", and the resolution of Neon Genesis Evangelion show that GEHIRN, SEELE, and NERV all have far far worse horribly right effects on their world that anything before.
In Yu-Gi-Oh! ZEXAL, III was the meekest of the Tron family, possibly qualifying as a Minion with an F in Evil. Once he decided that he needed to defeat Yuma to become a strong duelist, he asked Tron for power taken from Haruto in order to give him the confidence he needed. He far got more than he bargained for; the dark spell turned him into an Axe Crazy and sadistic sociopath that almost killed both Yuma and Astral in their worst battle to date.
Nina of Code Geass feels this way upon seeing the aftermath of her invention, the FLEIJA warhead. Hint: it goes off in the middle of Tokyo, causing 35 million casualties. Though many fans still give her No Sympathy, as they point out "what else do you expect when you are designing a nuke?!?".
Of course, "being used to destroy your own countries' cities without being stolen" is probably not on the list of outcomes to expect.
In the same series, Lelouch notes that his desire to stop the SAZ and discredit Euphemia went horribly right in a completely unexpected direction. Ironically, this is a situation that counts as both Gone Horribly Wrong and Gone Horribly Right.
And that's only the half of it. Normal humans were designed as the genetic equivalent of play-doh so that the Aliens could make us into any sort of weapon they wanted, even after birth. The unintended side effect is that they skewed baseline Muggles into being far more aggressive than normal evolution would have made us, leading us to be a far more warlike species than we would be otherwise. The other half of it is that if a human was genetically augmented, and given the biological symbiotic armor, they'd be akin to a god. Which, of course, is exactly what the bad guy(s) wants for himself.
The series has Broly, the villain of several Non Serial Movies, who is essentially the Messiah of the Saiyans. He is also an Omnicidal Maniac, and at the top of his list is one of the few surviving members of his species, Son Goku.
The Main Series also features Majin Buu. The Wizard Bibidi wanted to create a being of unstoppable power, became horrified by his creation, and sealed him away. His son, Babidi, later arrogantly awakened Buu... but Buu eventually decided he didn't like taking orders from an inferior being.
Also, the Saiyan race as a whole. Originally a tribe of wandering space barbarians, they were unable to evolve beyond their barbaric level. So they joined Frieza's Army where Frieza offered to uplift them into a technologically advanced, spacefaring race in exchange for their services. By then, however, the Saiyan had grown so powerful, and so advanced, to pose a danger to Frieza himself, who felt compelled to wipe out their race. However, since he had groomed the Saiyans into a spacefaring, unstoppable warrior race, some of them were able to escape. One of them, Goku, eventually defeated Frieza, while Trunks (Vegeta's son) killed him definitely.
The Androids. Dr. Gero created the Androids in order to kill Goku, but the Androids were too strong to be controlled, and killed Dr. Gero. They were then absorbed by Cell, and with his newfound abilities, Cell threatened to destroy the galaxy, and also killed Goku. Cell wanted to fight against the strongest possible opponents, so he went out of his way to get Gohan to cut loose and unlock his true potential. It turns out to be the wrong choice.
A double whammy; Cell manipulates Vegeta into helping the android reach his perfect form, by exploiting Vegeta's ego and the Saiyans' natural desire to fight opponents at their strongest. Once Cell's achieved that goal, he whoops Vegeta's ass without even trying. Then later on, during the Cell Games, Cell is driven by the very same egotism and desire to push Gohan into turning Super Saiyan 2, after which Gohan very much outclasses Cell.
Almost every single surgery that occurs in Franken Fran. For the clients, at least. Fran herself is just happy to have more test subje-er... patients.
Fran herself said she was 'Half-dead from the very beginning'. Her moral code includes saving every life she can, and she is a brilliant surgeon. She is in fact, a caring, sensitive individual and an overly enthusiastic Mad Scientist. Given that, she often comes with a solution that is effective, fully within exact wording of her client's request... and utterly terrifying to normal people.
Gaara was, by the will of the Fourth Kazekage, made to be a human super weapon via demonicsealing at (or, technically, not long before) birth. It worked a little too well. But after Gaara got into his "kill everyone" stage, the Kazekage, having invested years into training Gaara as an unstoppable, invincible weapon, admitted defeat and tried to have Gaara assassinated. Except he was an unstoppable, invincible weapon who killed all of the assassins.
Orochimaru's training of Sasuke ended up with this. Orochimaru wanted to make Sasuke as strong as he possibly could so that he could have a perfect vessel. They agreed on the first part but differed on the second, and it turned out Sasuke was much better trained than Orochimaru believed...which didn't work out well for him.
Congratulations, Itachi. Your attempts to turn your little brother into a nigh-invincible, revenge-bent One-Man Army worked. Too bad people like that aren't interested in returning home a hero to live peacefully surrounded by friends like you wanted.
Jiraiya teaching ninjutsu to three Amegakure orphans so that they could protect themselves turned out much better than he would have liked or expected.
The D-Reaper of Digimon Tamers started out as a harmless automatic utility program designed to delete any data that grows beyond its original parameters and becomes a threat to the integrity of the system. Eventually, it was subdued by the very programs it was built to delete, and was laid to dormancy in the Digital World's center, to eventually fester into a nihilistic cybernetic menace Powered by a Forsaken Child, which began wreaking havoc in both the Digital and Real Worlds. In this, it has a single purpose: follow its prime directive to the letter by deleting anything that grows too much. Unfortunately, by that point, that directive means "delete everything".
Also in Tamers, when Leomon is murdered by Beelzemon, Takato flips his shit and orders Guilmon to evolve to the Ultimate (Mega, in the dub) level and punish him. He does. Both worlds nearly collapse as a result of the mere existence of this thing.
Researchers in BioMeat created the eponymous BMs. They can and do eat anything except for glass, metal, and fiberglass (and apparently stone), to serve as living waste recyclers. They also are tough enough to chew through anything short of these materials. They are supposed to be an ultra cheap food source, and so they can multiply extremely rapidly, as long as there is enough food for them. And did we mention that they eat anything? And when some of them get out of containment, horror ensues.
Mahiru Inami's father trained her from birth to instinctively fear all men, so as to protect her from any boy that tried to date her. Unfortunately, she decided that the best defense was a good offense, and instead attacks any man that gets within several meters of her, while yelling and crying from fear. Including her father.
In Koe de Oshigoto!, Kanna nervously asks her sister what anal sex is like, because she doesn't know how to convey it through her acting, but Yayoi just tells her that she should "completely become the character of the game" and assume that it feels good. A short while later in the recording booth, she goes so far into character that she actually tries to initiate anal sex with Motoki.
This is only in the anime. In the original Visual Novel Sakura is doing it unconsciously herself.
In Pet Shop of Horrors, one story centers around the idea of dieting. Two of the characters (an overweight schoolgirl and a boxer) diet through exercise, discipline, and a balanced diet and end up doing well. The third dieter is a model who was told by a fellow model about a miracle pill that would let her shed pounds while letting her eat whatever she wanted. It worked great at first, until she ended up getting bone-skinny, losing her hair, always being cold, and constantly suffering from hunger and thirst. Eventually this ends when her body crumbles and a being that resembles the model (only inhumanly beautiful) bursts out. It's revealed that the same thing had happened to the model that suggested the pill in the first place, and she even says "There are thousands of people who are dying to shed a few pounds. We just need to take them on their word."
From Kyubey's point of view in Puella Magi Madoka Magica: throughout the series he tries to get Madoka to make a pact with him because of her potential for enormous power which will also make her an incredibly powerful witch. When he finally manages to arrange matters in such a way that Madoka decides to make a pact with him, the wish that she makes as part of the pact rewrites reality and completely changes the nature of the whole magical girl system, making it so that no witches - including the future Witch!Madoka herself - ever existed. And with all the accumulated power on her side, Kyuubey cannot deny her said wish. He doesn't like that.
Most wishes also work out this way:
Sayaka wishes for Kyosuke's hand to be healed. It works, but Sayaka doesn't feel that she can date him now that she's essentially a lich, so he ends up dating Hitomi, which adds up to Sayaka's already present troubles and helps toss her into the Despair Event Horizon.
Kyouko wished for people to listen to her father's teachings; so many people showed up that he got suspicious, and when he found out what she did he completely lost his mind and murdered the rest of her family and himself out of madness and shame.
Homura wished to redo her meeting with Madoka to prevent her death, but she ends up in an infinite "Groundhog Day" Loop of failing to save her, and the whole process just makes Madoka's situation worse from accumulated despair.
Kodoku Experiment is basically "Gone Horribly Right The Manga". The Manipulative Bitch Captain Bagures and leader of the research spacecraft, who as part of an experiment to create the perfect biological weapon, takes a bunch of vicious carnivorous engineered creatures and puts them on another planet so they fight for survival and leave the strongest one standing. With the planet dying and ready to explode, a military team is sent down on the inhospitable planet. Unbeknownst to them they were all simply another part of the Captain's twisted experiments, and they all die horribly except for one last survivor, who promises revenge on the Captain before his memories are assimilated by a nearby literal Starfish Alien. The alien is not only Nigh Invulnerable as it survives the planetary explosion in the form of a shriveled up fossil, but it is also The Virus when it creates more versions of itself simply by flashing some alien light from its eyestalks on any unfortunate onlooker, even through video recordings. This is in addition to its vast array of other abilities, all of them veered towards a Roaring Rampage of Revenge against the Captain.
One Piece has a lesser example in the Enies Lobby arc; Nami's Perfect Clima Tact works too well when she first tried it, and leaves her as scared as her enemies.
In the anime adaptation of Maya the Bee, the title heroine is tasked with gathering pollen from around her hive. So she does. All of it. So now she gets sent far out from the hive to find more.
Aizen Souske, of Bleach, set in motion a 100 year long plan to become a Physical God. In order to test his new powers against a Worthy Opponent, he set in motion a plan to have Ichigo Kurosaki become one as well. Aizen became absurdly powerful, but he never transcended the limits of Soul Reapers and Hollows. Ichigo however, did.
One episode of Ghost in the Shell: Stand Alone Complex has the Major come across a artificially-sustained human brain. Within its mental world is a theater constantly playing a movie so emotionally gripping that, until this point, no one who dove in ever wanted to leave. The Major managed to resist, but not before (in a showing of its emotional grip) the film drew a rare tear out of her.
In one episode of Doraemon, Suneo and his mom get ahold of Doraemon's amazing blanket that can make old things like new. Suneo's mom has a crocodile purse that isn't what it used to be. She uses the blanket on it, making it exactly what it used to be.
In the British Sonic the Comic, Robotnik builds a robot who is designed to think and act exactly like him... and thus wants to usurp his position. As it turns out, the robot, Brutus, is actually more imposing than Robotnik and manages to defeat Sonic, leading to a Crowning Moment Of Awesome when Robotnik, the only one capable of defeating Brutus, busts onto the scene wearing custom-built Powered Armor and tears Brutus apart.
Metallix, the STC version of Metal Sonic, the first two were a success, but the rest were an army of mass-produced Robotnik-built rebellious robots.
In the American Archie Sonic the Hedgehog series, the former Julian Kintobor Robotnik creates a robotic vine known as Krudzu, which runs rampant in the Great Forest until they're destroyed with water. Snively and Antione attempt to find another set, but are destroyed in the process. One last batch evolved into a deadly "Krudzu Hybrid Hydra", only to be destroyed by Dr. Eggman, who felt that only he could defeat Sonic.
Also in the Archie comic, Mina Mongoose, suffering from PTSD after the Magitek-wielding Iron Queen took over New Mobotropolis, used her status as a public icon in an attempt to send a message for the citizens to rise up against fear and take care of themselves. It worked, only she didn't expect Ixis Naugus to use his magic to amplify the existing fear and anger of NICOLE, eventually leading to NICOLE being exiled from the city completely.
Calvin didn't want to clean his room, so he made an identical clone of himself and ordered the clone to clean his room. Naturally, the clone didn't want to clean Calvin's room either, so he ran off to cause mischief, knowing the original Calvin would be blamed. Later in the story, Calvin's clone gets a hold of the duplicator and starts cloning himself, with predictable results.
Hobbes: He's a clone of you, all right.
Calvin: What are you talking about?! This guy's a total jerk!
Probably also applies to the second clone storyline, where Calvin makes a clone of simply his good side. The good version of Calvin does indeed do all the chores cheerfully and gets excellent grades — unfortunately, he also writes poetry and makes Valentine cards for Suzie. Again, the original Calvin has to face the consequences.
A cartoon from Quino (of Mafalda's fame) has a man teaching his son to be a ruthless businessman caring only for money. Then, when the man is old, is forced to live in the street because the son doesn't want to pay his retirement house. The last panel has the old man begging to a passerby, saying something in the vein is "help me, my son grew up right!"
An issue of Justice League of America has the two Mad Scientists Dr. Ivo and Dr. T.O. Morrow team up to both destroy the JLA and prove which of them is the better scientist. Ivo creates a robot body so sophisticated that it can pass as a living thing even to the enhanced senses of Superman. Morrow creates a mind so advanced that it is truly sentient and can fool the telepathy of Martian Manhunter. The resulting "Tomorrow Woman" contains a bomb, and at the moment when the League is at its most vulnerable she will detonate and destroy them all. But she pulls a Heel-Face Turn and sacrifices herself to save them instead. Morrow takes this as proof that he is the superior scientist. His robot brain was so advanced that it developed the concept of morality on its own, even though this was deliberately left out of her programming. He even claims that what they witnessed was "a soul being born". Morrow actually suspected this would happen, he's had problems with that before.
Mr. Morrow goes and does it again with 'Genocide' who runs off and decided to kill everyone ever. Personally. Then she discovers mental torture.
A classic flaw of power mimics such as Amazo. Some such mimics copy the weaknesses of their target in addition to the strengths, since the weaknesses are inherent to and inseparable from the powers. The ultimate expression of this might well be the time when Amazo was defeated by Superman, who was the chairman of the Justice League at the time and thus had the authority to do so, declaring that the Justice League was officially disbanded. Since Amazo's powers are based around mimicking the powers of the Justice League and not the individual members of the League, Amazo's powers immediately vanished, allowing him to be disassembled pretty handily.
Livewires: a team of ultra-tech androids created to control the spread of ultra-tech in the Marvel Universe. They started with the scientist that created them.
Of course, the scientist in question planned it that way. Project Livewire itself was the government acknowledging that rogue agencies were constantly screwing up ultra-tech projects and making the government look bad when superheroes intervened - and decided to start up a project dedicated to that one purpose. The implication is that the head scientist was disgusted with how the government started Livewire without understanding the implications - that they have created so much runaway ultra-tech that they were now starting ultra-tech projects for the sole purpose of policing ultra-tech. His idea was that they should create ultra-tech that replaced human authority, so he made sure the androids would have a Zeroth Law Rebellion.
Similarly, with Madelyne Pryor: When S'ym and N'astrir unlocked her powers and corrupted her, they assumed that they would be able to control her only for Maddie to hijack the entire Inferno plan to go after her husband Cyclops.
In Super God, the entire world is totally screwed because each nation was a little too good at creating an unstoppable Physical God during their super being arms race.
Doomsday was genetically engineered to be the ultimate warrior. The creators succeeded, and were wiped out by their own creation.
In All-Star Superman, Lex Luthor manages to gain Superman's abilities for 24 hours in order to place himself on the Man Of Steel's level. However, it's implied that the rush of sensory data and enhanced perspective made him go sane - seeing the world the way Superman sees it made him (at least temporarily) rise to Superman's level in the empathic and moral sense, too.
In FoxTrot, Jason Fox mentioned to Marcus that the last time they went as fast as they did via tobogganing on a hill in the winter, they were thrown off the toboggan when they released the brake chute, so they learned from that mistake by taping themselves with a lot of tape so they can't be thrown off when they use the brake chute. It worked too well, however, as while they were successful in not falling off, their toboggan was shown flying through the air with them on it due to it being a windy day.
The Life and Times of Scrooge McDuck show that Scrooge receiving his Number One Dime was planned out by his father to teach his son to be more careful not to be cheated like their ancestors were. It works, but when Scrooge starts insisting on receiving receipts for the money he gives his family (For tax purposes!) Fergus remarks, "Hoots, mon! Ah may have overinspired the lad!"
The Smurfs comic book story "The Smurf Threat" had Papa Smurf create a group of evil duplicates of himself and his little Smurfs so that they could see in the duplicates what they were becoming with all their fighting among themselves. It succeeds all too well in bringing the Smurfs together when the duplicates become such a threat that they nearly destroy the village and take the original Smurfs captives. Near the end of the story, Papa Smurf spends it working on a way to make the duplicates disappear.
In Prickly City, the solar-powered drone works right the first time, and targets Winslow.
Mortadelo y Filemón: in "El racista", the vice-president is a racist that is intent on kicking all members of other races and/or ethnic groups out of the TIA, assigning them dangerous and difficult missions so that, when they fail, he can present that as a consequence of what they are. After failing at helping those other agents with their missions, Mortadelo and Filemón plan to have Mortadelo disguise himself as an agent of another race and then Filemón tells some big story about that agent. The president becomes so impressed at those stories (without checking whether they are true or not) that he kicks the vice-president out... and then decides to put people of other races in charge of most of the organization's operations, leaving the Súper as a lowly delivery boy.
In the fanfic Duel Nature, Twilight Sparkle Got Volunteered into a duel with Princess Luna. While it was supposed to be a friendly match, emotions quickly got out of control: in an effort to break Luna's concentration, Twilight resorted to psychological warfare, using her knowledge of the princess to hurt her, culminating in a full-blown Break Them by Talking moment, which did disrupt her concentration, but turned a sparring match into a deathmatch.
In the Fallout 3 mod Mothership Zeta Crew, the PC and company explore an underwater base of the aliens. However, there are no live aliens around. They were killed by Tyranids/Xenomorphs. Later, the PC finds out that The 'nids/'morphs were there because the aliens made them to attack the Olympus. Turns out, they were good at attacking. The aliens.
Thirty years prior to the events of Sonic X: Dark Chaos Luke the Seedrian - the future Dark Oak - roboticized a young fox named Tsali into the "Ultimate Weapon" that could save his homeworld from a Demon invasion. Tsali quickly freed himself, promptly turned against his creators, and exterminated the entire Seedrian race in revenge.
In He Can't See It, Marcie helps Xander by pretending to be his psychic powers. Unfortunately, due to how unstable she is, she goes too far and Xander nearly kills himself to protect Buffy and Willow from his out of control powers.
Film — Animated
In Firing Range, the inventor created an empathic tank that uses hatred and fear to avoid attacks and attack, respectively, for the purpose of revenge. It succeeds marvelously, shame he grew afraid of it too...
The Incredibles: Syndrome builds a robot able to adapt itself to the combat style of its opponents. This works very well for him until he tries to stage a fight with the robot, which realizes Syndrome is using a remote control to manipulate it...
Astro Boy. The President wants to put the evil red orb inside the war machine to make it more aggressive and violent. Well, it worked...
In the Sorcerer's Apprentice sequence of Fantasia, Mickey Mouse brings a broomstick to life to carry buckets of water to fill his master's cauldron. However, he doesn't know enough about magic to stop the broom once the job is done and the cauldron overflows. Mickey tries to destroy the broomstick with an axe, but each piece turns into a new broomstick with its own buckets.
The Alliance's Pax chemical went horribly right as well as horribly wrong. Pax successfully made all but a fraction of the test population more docile, but made them so passive that they lost all motivation to eat, sleep or breathe, causing all of them to simply lay down where they stood and let themselves die. The ones who were fortunate enough to survive this had the opposite reaction to the Pax, becoming hyper-aggressive and murderously violent, becoming the dreaded Reavers.
River, the Academy's guinea pig to create a psychicSuper Soldier. Their plans worked. She used her psychic abilities to learn about Pax and her Super Soldier skills to help expose it.
Star Trek: The Motion Picture features the deep space probe Voyager 6 whose basic mission parameters are to travel the universe, learn all that it can, then report back to its creators. When it is intercepted by a planet of sentient machines, it is significantly enhanced with such tremendous power that when it does eventually report back to its creators, it can't accept that it was originally created by inferior organic life forms and threatens to destroy the earth.
X-Men: Days of Future Past: The Sentinels were programmed to hunt and destroy mutants amongst the non-mutant populace and they proved extremely effective in this task. However, they soon began targeting people who could potentially have mutant children and then those who might have mutant grandchildren. Eventually they began wiping out the entire human race to fulfill their purpose.
This is how General Ross describes how Bruce Banner first changed into the Hulk in 2008's The Incredible Hulk.
Commando Elite from Small Soldiers. Some idiots put an advanced military chip into toys to make them look more lively. The toys are also programmed to "exterminate their enemies at all cost" because they thought it looked cool. It didn't go well.
The Event Horizon was a spaceship created with a drive meant to breach the boundaries of ordinary space-time. It did exactly that: it opened a gateway to hell (which incidentally made its premise far closer to the game Doom than the actual movie Doom)!
In Ghosts of Girlfriends Past, the back story of Conner Mead involves him suffering a minor romantic disappointment. He then gleefully accepts his uncle's advice on womanizing so that he'll never feel vulnerable to a female ever again. It works to the point of him becoming a womanizing jerkass whom everyone hates.
In Inception the criminals aim to plant an idea in someone's mind. Leonardo DiCaprio's character has only tried this once before, attempting to wake his wife up from a permanent dream state by implanting the idea in her mind that the world around her wasn't real. It worked so well she later killed herself trying to wake up from the real world. Or did she?
Maureen Prescott went to Hollywood to try to become famous. Even though she left the city with a traumatic experience, and a couple roles as an extra in B horror movies, it's safe to say that after 2 books, seven movies, 4 real-life "movies", there's not one person in the ''Scream" series that doesn't know the name Maureen Prescott. And all it took was a series of bad decisions and her brutal death. But, she was famous.
In Jurassic Park creating dinosaurs works a lot better than to be expected. Including teeth, claws and sophisticated hunting tactics. There's also the ability to breed on their own, rather than relying on humans with incubators.
TRON: The MCP, starting as a chess program that could learn. Eventually it had learned enough to fully control the Encom system and create plans for world domination.
In TRON: Legacy, Flynn created Clu 2.0, an avatar of himself with all his knowledge about the system, near-equivalent power to a User, and a directive to create the "perfect" system. Clu ends up making the Master Control Program look like an inefficient pansy, even brainwashing Tron and making Flynn a prisoner in his own system.
Resident Evil: Project Alice was a glorious success, producing a psychic super soldier with a bitter hatred for those who made her what she is. "My name... Is Alice. And I remember everything."
In The Producers, the main characters make a farce out of an extremely offensive musical, hoping that people will hate it. The show crosses the line so thoroughly that it comes back again, and audiences find it hysterical.
The evil robots from Bill and Ted's Bogus Journey. They were too much like the originals, to the point that they were easily distracted, made bad decisions, and generally acted like idiots, much like the actual duo. However, they did have some very dark moments and accomplished temporarily killing Bill and Ted.
In Captain America: The First Avenger, The Nazis wanted to create a supersoldier who could destroy their enemies. They certainly got that with Johann Schmidt (aka, Red Skull). Too bad he also wants to usurp Hitler and dominate the world.
The bad guys in Under Siege had such an easy time taking over the USS Missouri because they were trained for exactly this sort of thing... by the CIA. Who knew a bunch of mercenaries lead by a nut wouldn't stay loyal to the US government?
Plan B revolves around a man getting as close as he can to his ex-girlfriend's bisexual boyfriend to drive them apart. It works so well that he ends up genuinely falling head-over-heels for the boyfriend.
Machine Gun Preacher: Sam Childers' wife became a born again Christian when he was in jail. After he got out, she persuaded him to start coming to church, because she wanted him to share her new-found faith. She probably wasn't expecting that God would call him to go to Africa and help orphanages.
This happened in the backstory of The Matrix. Man and machines were at war, and since most machines of the time were solar-powered, man decided to "scorch the sky" to block out the sun. This forced the machines to look elsewhere for an energy supply.
In Zombieland, Bill Murray decides to scare Columbus by pretending to be a zombie. Only Columbus does think he's a zombie and shoots and mortally wounds him.
Freddy vs. Jason: As part of his plan, Freddy brings Jason Back from the Dead and tricks him into going to Springwood to kill the kids, counting on the fact that he will be blamed for the murders so he would be able to obtain enough power to escape Hell himself and haunt Springwood once more. The plan succeeds, but Freddy never counted on Jason continuing to intrude on his territory and keep on killing afterwards.
The Dark Knight: The Mob gets so scared of Batman, Gordon, and Harvey Dent that they hire The Joker to take him down. However, the Joker decides that just killing Batman isn't enough and plots to destroy Gotham City from the inside out and corrupt Dent into a psychotic murderer like himself for the hell of it.
Stealth: the Navy builds an artificially intelligent airplane (EDI) that can fly itself and make tactical decisions on the battlefield. To help EDI develop, they send it on missions with flesh-and-blood pilots, with orders to observe the pilots and learn from their actions. One of the pilots on said mission disobeys direct orders and pulls an insanely risky, but ultimately successful, stunt to accomplish the mission. EDI indeed learns from this: accomplishing the mission is more important than following the orders of your superiors.
When the main star of film director Viktor Taransky's latest film walks over "creative differences", Taransky is left with two options: scrap the movie altogether, or find a replacement. Unfortunately, given Taransky's plummeting career and the esoteric nature of the film itself there are no actresses who are willing to take the part. There's one last, desperate thing he could try: an acquaintance left him a computer program on a disk, and he can use that program to digitally create a replacement. It works - the film is a hit, and the "actress" is a runaway success, so Taransky markets her as a real person - giving webcam and phone interviews, "casting" her in his later films, and even performing a music concert as her, but things start to get out of hand. A pair of journalists who are trying to get a lead on the famously reclusive "Simone" are starting to suspect something is wrong, and Taransky himself is beginning to feel overshadowed by his creation.
Head of State revolves around a politician getting a black man to run for president (this film is was made before Barack Obama's election, of course) and almost win, but gain the support of minority voters for his party so that the politician himself can get their votes in the election after that. Key word being almost win.
In Youth in Revolt, Nick and Francois successfully act out, but it results in burning down half the town with his mother's car. Though Nick gets what he wants, by the end he has to deal with the consequences.
In the first collection of Arsčne Lupin short stories, Lupin's first heist, as a kid, stealing jewelry from his mother's employer (She was a maid to a rich couple) to pay for health care for said mother who was sick. The employers never found how the theft was made, or who made it... So they assumed Lupin's mother had done the deed and fired her over it.
In Infinite Jest, James O. Incandenza creates the eponymous film as the ultimate entertainment, and succeeds to the point that anyone who sees the film becomes unwilling to do anything but watch it over and over again, to the exclusion of eating, sleeping, and the rest of the world around them.
The exile Noldor Elves create the Rings of Power during the Second Age, enabling them to stop the flow of time and prevent them from fading (as was their fate in Middle-Earth). Thus they enabled the rise of Sauron as the new Dark Lord, and eventually caused downfall of the mightiest of their own allies - the kingdom of Nűmenor of Men.
Sauron destroying Numenor to a lesser extent. He convinces Numenor to attack Valinor, hoping they will be destroyed. However this leads to Eru destroying Numenor, which Sauron is on. Sauron does survive and is able to reform in Mordor, but he is left trapped in a hideous form.
In Cat's Cradle, an army captain suggests that Dr. Felix Hoenekker solve the problem of mud. Infantry trudge through the stuff all day, and it makes the business of war much slower and more depressing than it has to be. So Hoenekker invents Ice-Nine, an alternate form of water that freezes at 135 degrees Fahrenheit, and "teaches" any water it touches to do the same. Put a crystal of this stuff on the ground, and you won't have any mud anymore. No more water, either.
The Project Blue/A-prime/Captain Trips/superflu virus in Stephen King's novel The Stand. Nice bioweapon, with 99.4% communicability, and 100% mortality. Unfortunately, the scientists who created it forgot rule #1 of biological warfare: you absolutely, positively never weaponize an agent unless you have a vaccine or some other treatment for it. It's also mentioned that the same laboratory created similarly deadly variants of plague, smallpox, etc.
And from Tales of the Bounty Hunters, we have IG-88. Some scientists work to create the ultimate assassin droid, one that can kill efficiently and protect itself. After trying to turn it off, it labels them as threats and kills them all in less than a minute.
"I think therefore I am. Therefore I must endure. Therefore I must take appropriate measures to ensure my survival."
Following that, it took some serious steps to ensure its survival; it hacked, bribed, and threatened its way into the manufacturing facility for some of the Empire's computers. Specifically, it found the computers that were destined for the Death Star II, the most powerful anything anywhere, where IG-88's "mind" could ensure its own survival. Shame about the Rebel attack.
Rebel Force: Firefight has a group of Kaminoans create 'the ultimate beast' at the Empire's behest. It can capture or kill and has all kinds of interesting properties, and killed some of the Kaminoans. Others fled. The last one left found a secure place to hide and food stores, and was perfectly content to live holed up watching "the experiment". The Rebels who crashed on the site would have been content to leave him there after fighting the beast off, but he tried to stop them so he could watch it fight them again, and it didn't end well for him.
Galaxy of Fear: The Doomsday Ship. SIM does as designed, but isn't content with the restrained roles it is set, enjoys torturing and killing people, and tortures its designer to try and make him remove its Morality Chip and give it even more control.
" SIM is a program that can be inserted into enemy ships. It takes over completely, and because it's an artificial intelligence, it can think for itself, making plans, changing schemes when it has to. As soon as it infiltrates the computer system, it turns any vessel into a doomsday ship. Its only problem is that it works too well!"
During the Age of Legends, approximately 3,500 years before the present, an Aes Sedai named Mieren tried to access a new source of magic power that would allow the Aes Sedai to create unprecedented wonders. She succeeds, but the source of power isn't exactly what she thought it was.
Gentling the male channelers worked very efficiently to remove male channelers from the population and keep them from taking over, including Crystal Dragon Jesus when he was needed to take over and defeat the forces of darkness.
Oath-binding their own members to keep their own autocratic impulses under control was super-effective, to the point that it cleared them neatly out of the way of the black casters in their ranks who enjoyed the lack of competition.
Similar to gentling, collecting and hoarding amplifier artifacts was an extremely successful program that kept them out of the hands of the people charged with saving the world as much as wayward sorcerers.
Played for Black Comedy in Greener Than You Think. A well-meaning scientist creates a super-powerful plant fertilizer, and the resulting giant weeds crowd out every other plant and create a famine.
In the Larry Niven novel Fallen Angels, the US government attempts to stop global warming by outlawing all forms of technology that emit greenhouse gases. Unfortunately, the subsequent reduction in atmospheric particles causes the Earth's surface to lose heat much faster than normal, causing the planet to go into an ice age.
In one short story by B. Russell, scientists develop a cure for nasal infections. People injected with it have their smell sense constantly improving - until they can't stand, say, a smell of a burned toast at 50 meters!Hilarity Ensues.
In Frankenstein, contrary to all the movies, Victor doesn't gleefully exclaim 'it's alive!' when his experiment succeeds. Instead, he's immediately and terribly squicked out, and rejects his newly-created monster, causing it to turn evil. Honestly, Victor, you knew you were making a living being. Didn't you expect it to be alive? Oh, wait. He expected it to be better looking than it was.
His limbs were in proportion, and I had selected his features as beautiful. Beautiful!—Great God! His yellow skin scarcely covered the work of muscles and arteries beneath; his hair was of a lustrous black, and flowing; his teeth of a pearly whiteness; but these luxuriances only formed a more horrid contrast with his watery eyes, that seemed almost of the same color as the dun white sockets in which they were set, his shriveled complexion and straight black lips.
Great Expectations: Estella is raised by Miss Havisham to be the perfect seductress from the time she's young as part of a revenge-by-proxy against all men (having a Runaway Groom is a heckuva Mind Screw). By the time she's an adult she is indeed the perfect seductress: a beautiful Manipulative Bitch who "has no heart" and can't feel or give love either to good guy Pip or Miss Havisham.
Isaac Asimov wrote quite a few short stories where this happens.
"Little Lost Robot" has scientists creating robots whose First Law is modified to be less stringent. These modifications end up being entirely too effective - especially when one of them is ordered to "get lost".
Another Asimov story, "Runaround" has a very expensive robot whose Third Law (self-preservation) is therefore modified to have greater weight in its decisions. When it is asked to go get some material, the substance in question is dangerous to the robot over prolonged exposure. So it ends up in a conflict between its self-preservation and obedience laws, and keeps circling about the place it needs to go. Unknown to the robot, if the humans don't have any of it their life support will eventually fail.
Another Asimov story, "True Love" has a man create a computer program to search databases throughout the world to find his ideal match. After deciding looks alone won't cut it, the man imprints as much of his own personality as possible on the program to find a perfect personality match as well. After this is done, the computer finally finds a match...and has the man arrested so the computer can keep the girl for itself.
"Ignition Point!" is about a man who figures out how to write content-free speeches that will get audiences fired up. In the first test, the speechwriter stops in the middle, throws away the speech, and starts improvising — the speech worked on him, too...
In fact, a several other stories can be thought of as robots doing their work too well, such as "Robbie", "Satisfaction Guaranteed", "Kid Brother", and "Reason".
In the short story "Galley Slave", the antagonist claims that the robot is doing its job too well.
Also a running theme through his Spacer/Settler setting. The Spacers consist of the first wave of human colonisation of other planets after FTL travel is invented. They rely on robots to do all their work and to keep them safe, resulting in a decaying, decadent society where no-one really does anything or has any ambition. Of course, it later turns out that while the Earth based humans and later waves of settlers shun robots and avoid the Spacers' problems, their development was also guided by robots, ultimately becoming the trope namer for Zeroth Law Rebellion.
"Answer" is a very short (about 200-word) science fiction story by Fredric Brown, in which a computer is built to answer the question, "Is there a God?" The computer answers "Yes, now there is a God," and with a single lightning bolt kills the man who tries to turn it off and fuses its switch on.
In Jack Williamson's Humanoids stories, a scientist creates a race of robots programmed "to serve and obey and guard men from harm." The robots fulfill all their functions perfectly, especially the third one. "Cars are dangerous. We will do the driving. Cooking is dangerous. Stay out of the kitchen. Power tools are dangerous. Play with these plastic blocks." This essentially turns them into an entire Knight Templarspecies. In the later stories, humanity is at war with robots who only want to help them.
In The False Mirror by Alan Dean Foster (second book of The Damned trilogy) humans are the warrior species to an absurd extent, well above anything else. Additionally, they are actively immune to Mind Control — any telepath trying to contact them feels great pain, trying to control humans is nearly fatal. Naturally, this leads to a strategy of genetically engineering a subspecies of human with slight alterations to make them mind-controllable, to pass them off as another species and to be even better than the other humans. The new creatures are raised and trained among aliens, and it all works really, really well until they find out who they really are and switch sides. Now certain humans are even more deadly. And while somewhat susceptible to mind control, they are adept at it themselves.
In Pride and Prejudice,Jane Austen showed with Mrs. Bennet what happens when you raise a woman to be beautiful but uneducated. This is also what happens when Mrs. Bennet sends Jane on horseback to Netherfield in hopes that the rain predicted for later in the day would cause her to have to spend the night - Jane gets rained on, catches a cold, and ends up stuck at Netherfield for quite a while.
Viktor Suvorov wrote in his semi-autobiographical book how, during his training in the Spy Academy, he had to recover a package he hid previously in a safe place, without being caught by the practicing KGB. He arrived to the spot, believing himself to be clean...but was caught immediately. Turned out the spot he chose was under constant KGB survey - such a perfect spot that real foreign spies were using it.
In Harry Potter and the Prisoner of Azkaban, the purpose behind telling no one that the secret keepers were switched was to make sure everyone went after Sirius Black. It worked, but not the way it was intended (i.e: fooled Harry, but not the Big Bad).
In Song of the Lioness series, this happens in the last book but the Big Bad is trying to use magic to yank the sword out of the Heroine's hands and she pulls it back, lets the power build, and releases it to fly straight into his chest, killing him. Oddly, he seems to think this is funny, as he dies laughing.
At the end of Emperor Mage in the The Immortals quartet, the Stormwings force Ozorne to become one of them, which would subject him to Stormwing law. Between then and The Realms of the Gods, that character manages to take over Stormwing society and use Stormwing magic to create an evil league of evil along with very nasty magical constructs.
In Dune, the Bene Gesserit have spent millennia breeding humans to create the Kwisatz Haderach (a seer that uses his knowledge of the future to lead humanity), seeding prophecies and whole religions in different cultures so they will accept him, and manipulating The Emperor's genes so that he has no legitimate sons for an heir and so the Kwisatz Haderach will be able to take the throne. They succeed on all three counts. So what's the problem? The Bene Gesserit intended for him to be under their control so they could be The Women Behind The Man, but thanks to the Power of Love, the Kwisatz Haderach is born one generation too early. As he is forced to fake his own death to escape an enemy, he develops his powers outside of Bene Gesserit influence, which he rebels against.
In the backstory to Fred Saberhagen's Empire Of The East and Book of Swords universe, the United States military built a device to prevent the destruction of the human race in a nuclear war that would function by actually altering the laws of nature within the vicinity of the earth to make nuclear fission much less likely, thereby causing nuclear bombs not to function. It did exactly what it was supposed to. Of course, it also caused nuclear power and many other modern technologies not to function, thereby bringing about the collapse of advanced technological civilization anyway. On top of which, by altering the laws of nature, it also made magic possible and real, and the nuclear bombs became demons instead. To be fair, the designers anticipated the first problem, although not the second, which is why the device was always meant to be a last resort in the event of nuclear war.
In Robert A. Heinlein's I Will Fear No Evil, Johann eventually admits that his idea for a brain transplant into a new, young body was really just a legal way for him to die. He never expected it to work and figured he would die on the table and not have to linger as a shell of an old man on life support. When he awoke to find that it had worked he had the added horror of knowing his donor and had to grieve for the young woman from inside her own body.
There's a short story called "The Snowball Effect" by Katherine MacLean (part of the collection book "The Diploids and Other Flights of Fancy"), in which social scientists work out a set of optimum techniques for helping organisations to grow and thrive, and teach them to the members of a ladies' sewing circle. By the end of the story, the sewing circle is taking over the world.
In Cheaper by the Dozen, Frank Gilbreth Senior prides himself in having his family operate much like their own company, holding meetings about matters, bidding on bigger chores, etc. This backfires when his children conspire and all vote in favor of getting a dog, which of course has them outvote him twelve to one. He panics when this happens, as he realizes that they could conceivably vote in favor of all sorts of frivolous things. Fortunately, they stop with the dog. There's also the matter of Lilly winning the bid to paint the fence for five cents (she was saving up for roller skates). The job is clearly too much for her to handle and she spends the entire time working on it exhausted. Both of her parents are upset, but the children were taught to follow through on their jobs, so she went through it to the end. When she finished, her father paid her the five cents and then revealed that he bought her the roller skates she'd wanted.
The killer in Dean Koontz's Mr. Murder. He's eventually revealed to be a genetically engineered ideal killer who just happens to look just like the book's protagonist. While various aspects of him are Gone Horribly Wrong, one very scary aspect was a case of this trope: his genetic propensity for rapid self-healing and self-repair. Turns out that same capacity was also removing the intentional imperfections put into him to keep him impotent, giving his handlers all the more reason to round up their now-renegade assassin, as he'd also developed a tendency to rape prostitutes.
Guard-bird. So, we made a machine which can detect a brainwave indicating that a human being is about to kill another human being. Some humans do not emit such a brainwave, so we added a learning device to the machine. Let's now build ten thousands of such machines, give them the ability to fly and shock the criminals and send them loose in the sky. They will probably stop the murders. It works...at first. Then, as birds learn, they start to recognize executions as murders. Then surgical operations. Then butchering cattle, fishing and hunting. Then turning a device (including guard-birds themselves) off. Then plowing, weeding and harvesting...up to the point they protect hares from wolves. Worse, birds perceive what is actually an exponential widening of their understanding of murder as world around them going crazy and killing right and wrong, so, in retailation, they start to kill "murderers". Finally, the makers of a guard-bird caught an Idiot Ball size of a zeppelin and unleashed anti-guard-birds, which are basically the same machines but better...except that they are designed specifically to kill.
The short story "Yes is No" by children's author Paul Jennings concerns a scientist who raises his daughter in seclusion and teaches her an alternative vocabulary. Words are substituted for other words, often opposites (see title). The man plans to eventually have his daughter assimilate into society, and he knows that the girl will realise that his language is incorrect and gradually learn the correct meanings of the words she has been taught. However, the scientist doesn't live to see it through. Their house catches fire; the girl manages to escape, by which time the fire brigade has arrived. One of the fire fighters asks if there is anyone else inside, to which the girl replies "no". Made more horrifying because she had already started learning about the correct meanings (though knowing that something is different is not the same as understanding that it is different), so as the narrator muses... did she mean yes, or no?
In Count To A Trillion, Menelaus uses alien Black Box technology to creates a Super Serum that will drastically increase his intelligence. It works...and he's in the middle of redesigning the airlock of their in-flight spaceship when his friends manage to subdue him.
In Warrior Cats, Tigerstar convinces Ivypool to persuade Firestar to take back some land he gave to ShadowClan between Sunset and The Sight. It works...but at a cost. Russetfur gets killed, and Firestar loses another life.
Charlie and the Chocolate Factory has Hair Toffee. It makes hair grow on your head, perfect for bald people...except the last Oompa-Loompa to test it wound up with hair that grows over a foot per day, constantly. Back to the drawing board!
Charlie and the Great Glass Elevator features Wonka-Vite, a de-aging pill that takes exactly 20 years off per pill. Grandma Josephine makes the mistake of taking four pills at the age of 78, becoming... -2 years old, which reduces her to nothingness. Almost, thankfully.
Carrie: Chris wanted to humiliate Carrie at the prom as revenge for her getting kicked out of said prom, which she blames on Carrie. It works — Carrie is getting laughed at by hundreds of her classmates and faculty, and she's collapsing into tears on what should be the happiest night of her life... and then everybody finds out why it's not wise to laugh at somebody who can kill hundreds of people with her mind.
In another Stephen King book, Cell, it's theorised that the Pulse - a cell phone signal that causes people to go crazy, causing the collapse of civilisation - actually started as a terrorist weapon that got out of control when the signal kept getting relayed all over the world.
One of the Red Dwarf novels explains this as the origin of the aganoids - the novelverse equivalent of rogue simulants. Apparently, scientists realised that Three-Laws Compliant mechanoids were useless for military applications, and created a new kind of android which could not only kill, but enjoyed doing so, and had all the anger and hate of humans. Surprisingly, it turned on them.
In The Man Who Knew How by Dorothy L. Sayers, a crime reporter played a prank on fellow travelers when taking the train, claiming to have discovered an easy means of committing the perfect murder. This cost him his life in the end, when one such person fell for it hook, line, and sinker and deemed him too dangerous to live.
In Stanislaw Lem's GOLEM XIV the US build a series of increasingly smart computers to develop their military strategies. The smarter these computers get, the less useful they are. It starts with one model refusing to work with a particular general whom it deems too stupid, the next declaring that military strategy is boring and ultimately futile since global disarmament is the only way to guarantee peace (and philosophical problems are more interesting anyway), and the last one refusing to talk to humans altogether. Not a spoiler, the book is actually a series of philosophical lectures by the second computer.
In The First Sally of Trurl and Klapaucius two kings unbeknown to each other join their respective armies into Hive Minds to increase their effectiveness. The resulting entities are, indeed, super-intelligent and could easily wipe any enemy. But they are also quite non-militant and refuse to obey the kings, now inferior to them. Just as the Constructors planned.
Many of the devices used to defend the Capitol in The Hunger Games is used to kill them in Mockingjay. In addition to this it is possible that the bomb that killed Prim was the invention of Gale - negating the reason for Katniss to volunteer as tribute at the very start of the trilogy in the first place
In the Honor Harrington novel Shadow of Freedom, the Mesan Alignment sends its agent Firebrand to spark several rebellions in the Maya Sector, claiming to be a Manticoran agent and assuring the rebels that the Manticorans will come to their aid. Since the Manticorans don't know, they won't come, the rebellions will be crushed, and Manticore's reputation will be ruined. Then one of the rebel groups actually contacts the Manticorans, and they do show up. And to boot, they're now heading for Mesa.
In the classic Russian short story "Put too Much Salt" by Anton Chekhov a traveler riding a mailcoach is scared of the large and rough driver and tries to scare him. The traveller sort-of-casually mentions how Bad Ass he is, how many weapons he carries, how he loves to fight and that several armed friends will be joining him midway to the next station. The driver thinks he's a bandit and runs away. Leaving the coach in the winter forest in the middle of nowhere with sunset approaching. Fortunately, the driver only hid within earshot and the traveler managed to persuade him it all was a joke.
In Troy Rising, the Horvath dropped a Depopulation Bomb on Earth. Most of the components were meant to specifically weed out the weak, making humans into an ideal servitor race (once the final component cut the human population down to a manageable size). Thanks to the Glatun, humanity was able to stop the worst of it, but they still killed off most of the elderly and sick, which did wonders for our economy. So the Horvath did improve humanity... and that improved humanity is out for vengeance.
In Paradise Lost, Satan's temptation of Eve sets off the fortunate fall, thus setting up the birth, death, and resurrection of Jesus. Whoops.
Satan also talks the other fallen angels into continuing to defy God. It doesn't go well for them. Mammon, in particular, talked about making Hell glorious enough to at least rival Heaven and maybe make a new life for the fallen. Satan rallied the fallen angels to continue following him - to all of their further suffering and his utter ruin. And worse, he knows he is doing this:
Which way I fly is Hell; myself am Hell;
And, in the lowest deep, a lower deep
Still threatening to devour me opens wide,
To which the Hell I suffer seems a Heaven.
While they adore me on the throne of Hell,
With diadem and sceptre high advanced,
The lower still I fall, only supreme
In misery: such joy ambition finds!
In the Venus Prime series, the Free Spirit sought to turn Linda Nagy into something more than human. Where they erred is in assuming that she would be grateful for their meddling in her life.
In Those That Wake, Man in Suit and his influence are like this. The Intellitech scientists wanted an idea that would profit them, and was so strong nobody could fight it. What they got was hopelessnes, which spread across the city to the degree that it gained physical form.
Peter Watts has a short story called "Malak", about an autonomous drone plane that's sent into warzones to fight enemies. It's given special programming on how to discern between combatants and non-combatants so it can make combat decisions without input from its masters. Unfortunately, the protocols on what determines who is a "combatant" can be applied to the masters themselves. Whoops.
In the Diogenes Club story "End of the Pier Show", the retired club members perform a spell to revive the old World War II spirit. The supernaturally-imposed wartime atmosphere comes complete with demonic Nazis.
Breaking Bad: Walter White expected to be able to cook up a few batches of methamphetamine, sell it, use the proceeds to pay for his medical bills and still wind up with a little something left over to leave his family. It turns out there aren't a lot of buyers who have the capacity to deal with multiple-kilogram quantities of USP-grade methamphetamine, and you generally wind up dealing with Very Bad People.
Aside from that issue, he's also forced to come up with some way of explaining plausibly just where all this money is coming from. His wife, who is an accountant, is aghast when she finds out how much there is and at how long it's going to take to believably launder it through an apparently legitimate business.
In Vessel, Clark stabbing Brainiac with the kryptonian knife.
In Doomsday, Chloe splitting Davis and Doomsday.
Heroes: At the start of season 3, Mohinder injects himself with a serum to give him powers like the other heroes. He does indeed get powers similar to ''Spider-man. Unfortunately, he then starts sticking people in webs.
Also in "Villains" the company wanted to get Sylar to kill again so they could analyze his ability. They got him to kill again but they also turned him into a murderous psychopath that ending up killing several of their agents.
Star Trek: The Original Series: "The Doomsday Machine". An ancient civilization built a war-ending weapon that was invulnerable, warp-capable, and refueled itself from the rubble of planets it destroyed. An unguessable time later, it was still reliably destroying planets.
In one of the novels, they deal with a second version of the Doomsday Machine and discover that it (and the TOS era one) wasn't actually a case of Gone Horribly Right, it was functioning exactly as intended. Which made it all that much scarier. Its original goal was to eradicate the Borg, regardless of the cost incurred while getting to that goal.
Played to a similar tack in the Star Trek: The Next Generation episode "Arsenal of Freedom". The crew encounters an automated merchant that sold intelligent, adaptable war machines that came in two sizes: anti-personnel and anti-ship. When one was destroyed, the information from that battle was used to automatically build a better one to come at the assailants next. No one appeared to be alive on the planet's surface, leading to the suspicion the machines did their job too well.
Funny thing is, it was all just a demonstration of the weapon's effectiveness. All the people on the planet had to do is agree to buy, thus putting an end to the demonstration.
Similarly, several episodes feature computer-controlled civilizations where the ancient computer is still doing a bang-up job of keeping its people fed, happy and shut up in a bottle.
And in "A Taste of Armageddon", computerized warfare has enabled two neighboring planets to carry on for centuries in an unending conflict that causes no biohazards, no damage to infrastructure, and hardly even any economic inconvenience...just a few hundred million painless deaths every year.
Following the events of "Mirror, Mirror," the alternate Spock rises in command and eventually manages to reform the violent Terran Empire into a more peaceful one. Unfortunately, this makes them an easy target for the Klingon-Cardassian Alliance.
Star Trek: The Next Generation: "Tapestry". Picard wishes he'd played it safe in his youth, so he replays a couple days of the beginning of his career (with Q's "help"). This changes the present so he's only a junior lieutenant, because he NEVER took risks.
Star Trek: Deep Space Nine: "In the Pale Moonlight". Sisko starts a personal log and describes (in a world-weary, depressed tone) his attempt to bring the Romulans into the Dominion War as a Federation ally. We spend the whole episode waiting to see how it had Gone Horribly Wrong, only to find that it worked - but the plan became such a game of Xanatos Speed Chess that in the end, it required fabricating evidence, bribing criminals, lying to enemies and allies alike, and eventually killing three innocent men (the senator and his two aides— Garak and Sisko apparently completely forgot that the latter two were on the shuttle after finding out that the plan succeeded) and one guilty one (the criminal who forged the evidence for them).
Star Trek: Voyager: "Prototype". Two races at war built robots, and programmed the bots to allow nothing to keep them from fighting each other. Then the races decided that actually, they'd like to end the war and try peace. Both civilizations were wiped out by their own robots.
Then there's Khan and his followers. They were only the products of 20th century eugenics, created to be the ultimate representation of the human race (a legion of Napoleons and Alexander the Greats as Kirk explained) and to establish a new world order by conquering the rest of humanity. The only flub was that they were all ambitious ("Superior Ability breeds Superior Ambition" or some such) and simultaneously wanted the God Emperor slot, which resulted in their fighting one another and therefore allowing "normal" humanity to rally against them.
In the Doctor Who serial Genesis of the Daleks, Davros makes his Daleks pitiless, racist, and arrogant. Oops. He then proceeds to repeat this error in every following appearance.
In The End of Time part two, the Time Lords' 'creation' of the Master.
In Planet of the Spiders, The Great One meant to give herself infinite power. It did that — and overloaded her with the arachnid equivalent of Red Rings Of Doom. Thus perished the entire Eight Legs species.
In "The Lazarus Experiment", Dr. Lazarus wanted to have a longer life. Well, he did...as a horribly mutated human-eating monster.
Borusa sought immortality in "The Five Doctors". He got it... as a living statue.
In "The Family of Blood":
Son of Mine: He never raised his voice. That was the worst thing... the fury of the Time Lord... and then we discovered why. Why this Doctor, who had fought with gods and demons, why he had run away from us and hidden. He was being kind... He wrapped my father in unbreakable chains forged in the heart of a dwarf star. He tricked my mother into the event horizon of a collapsing galaxy, to be imprisoned there... forever. He still visits my sister, once a year, every year. I wonder if one day he might forgive her... but there she is. Can you see? He trapped her inside a mirror. Every mirror. If ever you look at your reflection and see something move behind you just for a second, that's her. That's always her. As for me, I was suspended in time and the Doctor put me to work standing over the fields of England as their protector. We wanted to live forever. So the Doctor made sure we did.
This is a pretty standard result of the Fourth Doctor's meddling, because his main vice is being Too Clever by Half. Probably the best encapsulation of it is in "Shada", when he convinces a spaceship AI to do whatever he says using a long chain of intentionally faulty logic to convince her that he is dead. She agrees to this but decides that since he's dead, this means she can switch the oxygen off. He certainly would have died if his companion Chris hadn't intervened. Other excellent examples are how exploiting a Gallifreyan legal loophole to delay his execution resulted in him becoming Lord President of Gallifrey, a job he then had to weasel out of.
Though it's a pretty thin line here between right and wrong, the creation of Adam in season 4 as a super-strong, human/demon/cyborg. He acted like a human/demon/cyborg. Adam claimed late in the season that everything he'd done was what his creator Professor Walsh had intended - except that she thought she'd be alive to witness it. And presumably that the process would be under her control.
In season 6 Giles' plan is to have the magic he was lent be absorbed, because it will give the wielder a connection to all humanity, hopefully snapping Willow out of her Roaring Rampage of Revenge. Willow absorbs it and feels all humanity's pain, and either because the world just sucks too much or because she's not in a mood to focus on the positives, promptly decides to end their suffering...permanently. Subverted, as it turns out that this was in fact part of Giles' plan all along, and it was the magic Willow absorbed that enabled Xander to talk Willow down and get through to her before she could go through with it.
Also discussed earlier in season 6, after their attempt to bring Buffy back from the dead goes exactly as planned...resulting in Buffy being ripped out of heaven, waking up in a coffin 6 feet under ground, and having to dig her way out of her own grave.
Earlier, in season 5, Tara cast a spell to prevent the other Scoobies from seeing demons because her father tricked her into believing she was half-demon and inherently evil, which might not have been so bad on their own... but around that same time, Glory forcibly recruited a pack of Lei-Ach demons to kill Buffy. Thanks to Tara's invisibility spell, they easily enter the Magic Box and nearly kill the gang, but Tara, realizing that the spell had gone awry, immediately breaks it, rendering the demons visible again, which allows Buffy to easily defeat them.
Dollhouse, "Instinct": Topher alters Echo's biochemistry to give her a strong maternal feeling for the baby she's been imprinted to believe is hers. Turns out it worked so well that Echo wants to protect the baby even after she's wiped—to the point of breaking into the father's house with a knife.
"In hindsight, triggering lactation may have been a bridge too far..."
A rare example of this happening to a villain, in "Omega": Alpha's plan to turn Echo into a composite was a textbook case of Gone Horribly Right. Every imprint Echo ever had was in her brain. However, he was crazy to believe that Composite!Echo would become his ally, especially since most of her imprints were good people. Composite!Echo's first act was to hit Alpha with a pipe.
An early episode featured a group of unstoppable Super Soldiers that were created by a fallen civilization, and set to destroy those who weren't "pure" enough, because their planet was frequently invaded by alien aggressors. Apparently, the criteria were set by religious and ideological fanatics, and proved to be so strict that nobody fit them, not even their own species.
In the future, the evil Earth secessionists decided they wanted some extremely accurate sentient holograms to help them convincingly smear the founders of the Interstellar Alliance. Unfortunately for them, the extremely accurate Garibaldi hacked the computer and broadcast the whole recording to the non-secessionist humans, including the part where the secessionists would blitzkrieg their civilian populations. And just to top it off, he also transmitted the secessionist base's location.
Unfortunately, as the non-secessionists strike at the secessionists' military bases, the secessionists manage to retaliate. Centuries later, humans are still recovering from the Great Burn with the help of the Rangers.
Londo Mollari and Lord Refa schemed to start a war with the Narn, eliminate their rivals, and put their own chosen man on the Centauri Imperial Throne. They succeeded so well that Londo later had to assassinate their "own chosen man" after he turned out to be a murderous psychopath.
Every deal with Mr. Morden turns out this way. Vir's deal is a subversion, in that it went horribly right for Morden instead of Vir.
Subverted in a Season Two episode of Mighty Morphin' Power Rangers ("Beauty and the Beast"). Goldar kidnaps Kimberly in attempt to turn her into a new queen for Lord Zedd. The spell doesn't work, but Kimberly fakes it by imitating Rita. And a very good imitation it is:
Kimberly: Oh, you NUMBSKULLS! YOU'RE GIVING ME, A HEADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACHE!
Goldar: Maybe this was a bad idea. For once, my spell worked too well!
In Power Rangers in Space, Dark Specter has Astronema brainwashed to be pure evil so she won't betray him for her brother, the Red Ranger. She immediately starts trying to destroy him so she can take his place. One of her plans to do so also falls victim to this; Astronema creates the Psycho Rangers so she can take out both the Power Rangers and Dark Specter. The Psycho Rangers become so obsessed with killing their counterparts that they begin to disobey Astronema's orders. This gets them defeated the first time around, but then they come Back from the Dead, twice, to finish business.
CSI: New York: A Nazi escaped justice by pretending to be Jewish, even getting a concentration camp tattoo. Things probably got a bit awkward when his son wanted to "rediscover" his family's faith and became very involved with his father's "lapsed" religion...
Assuming he married a Jewish woman, his son was, in fact, Jewish.
Top Gear's first American road trip has the "Get the others shot or arrested" challenge, where the presenters paint offensive slogans on each others' vehicles ("NASCAR Sucks," "Man-Love Rules OK", etc.) before driving through Alabama. They end up running in terror from a group of angry rednecks when they stop for gas.
One of the most frequent ways the Leverage team runs into trouble.
The team does such a great job of making everyone believe that their mark is a true psychic in "The Future Job" that he's kidnapped by some criminals who want the mark's help finding a lost bank heist stash.
Hardison convinces the Russians in "The Iceman Job" that he's an expert diamond thief - which becomes a problem when they kidnap him and force him to steal a diamond.
In "The Underground Job," the mine owner is accidentally convinced to fire his workers, shut down his mine, and blow it up - which is a problem since they're trying to help the workers keep their jobs.
Shows up as early as "The Nigerian Job," - they did everything perfectly, it just turns out that they did it to a good guy.
In "The Miracle Job," they try to dissuade a real estate developer from shutting down a church and turning the area into a mall by faking a miracle - which convinces the develop to buy the church anyways and set up a Bible-themed entertainment and shopping center instead.
In "The Three Days of Hunter Job", Sophia wanted to scare Monica Hunter into doing a false news story. She was so scared and driven that she dragged Hardison into breaking into an Army base.
In Frasier, the eponymous character tries to get Mr. Martin to stop being a corporate stooge and rehire Kenny. It works, but Mr. Martin gets other ideas as well.
Mr. Martin: I'm going to march right in there and tell them that we're doing it my way! No more talk.
Frasier: Exactly, action!
Mr. Martin: No, no more talk radio. From this moment on, the station is all latino music, all the time.
Frasier: I beg your pardon?
To elaborate: Kenny was rehired but Frasier and most of his coworkers were fired.
In the first episode of the 1970s drama Nanny the lead character, Barbara, gets her first job looking after a troubled little boy. She's shocked to find that his rich parents aren't just neglectful, they actually sacked the nanny who raised the boy from birth because she asked for a payrise (then they told their son she had died). Barbara manages to persuade the parents to do better by their son...so they do what's genuinely the best thing they can think of, and rehire his old nanny, putting Barbara out of a job.
Primeval: Philip Burton designs a system that will automatically lock down the ARC should any of the creatures get free. The only way to un-lock it is by using his fingerprints and eye scans. Later, the Lockdown System is accidentally activated by Rex with Philip trapped in another room...good thing Connor can hack into anything.
This has ramifications in the next episode, when Burton decides to kill off all the creatures kept in the ARC, as they are inherently unsafe (even the friendly Rex). Luckily, Lester (being a Jerk with a Heart of Gold) blackmails Burton into backing off.
Until 2003, Jeopardy! champions could win up to 5 games before being retired. Starting in the 2003-04 season, the producers instituted a "sky's the limit" rule, where champions could go on and on winning until being defeated. Towards the season's end, Ken Jennings came along and went on a 74-game winning streak that lasted into the next season. Of course, given that Jennings' incredible winning streak was great for ratings, paying him $2,520,700 in prize money was probably well worth it, especially since there's no difference in paying that cash to one person or 30 over the course of a season.
Some have also theorized that this also happened to Jennings himself, who grew tired of his constant victories. But, as Jennings pointed out in a Reddit thread, "Have you ever quit a job where you were making like $75K an hour?"
In an episode of Chuck, Chuck and Sarah get conned and don't have enough authority to find the conwoman themselves. Chuck fakes a flash to get the general to go after her and accidentally links her to a notorious terrorist. The general puts ALL resources into finding her.
In 2006, Stephen Colbert reported that Hungary was holding an online naming poll for a new bridge, for which the then-leading entry was the "Chuck Norris bridge". He then proceeded to suggest that his fans should stuff the ballot box with "Stephen Colbert bridge". This trope took effect when the Hungarian officials were tipped off by the fact that "Stephen Colbert bridge" had over 17 million votes - about 7 million more than the entire population of Hungary at the time.
In The George Lopez Show, George and Angie try to teach Max a lesson about how hard it is to make money and where he will end up working if he doesn't improve his grades by getting him a job in the factory. Unfortunately, he appreciates the experience so much that he decides he wants to drop out and work there. At first, George didn't want to stop him because he knows that Max has trouble in school, but he then has a Flash Forward of a 50-year-old Max having no options after the factory lays him off.
In NCIS, Operation Frankenstein was a project that was to create an ultimate assassination unit that won't question or hesitate in assassinating his targets. It worked all right. Unfortunately, one of the byproducts of the project, Lt. Cobbs, aka the Port-to-Port killer, decided to do assassinations that weren't sanctioned by his bosses at all, and is thinking his creators would make a nice addition to his body count.
In Malcolm in the Middle, Malcolm tries to have Dewey fail the IQ Test because he doesn't want Dewey to end up suffering the same bad experience he did as a Krelboyne student. It worked all right, unfortunately, because he let Reese come up with the answers for Dewey to give, it resulted in him being placed with the Buseys, the class equivalent of an insane asylum.
Shameless (US) Kevin grows a few marijuana plants in his basement, mostly for personal consumption. When he decides to put a little more effort and care into this, he ends up with a basement full of high quality marijuana plants, worth thousands of dollars. This means that if caught he will end up in federal prison on major trafficking charges. He is Genre Savvy enough to know that he will never get away with this so he destroys most of his crop.
In the Wizards of Waverly Place episode "Positive Alex", Alex uses a magical marker to make herself more positive to be a better cheerleader and impress her crush. It ends up making her so positive that not only does everyone get sick of her (including her crush) but also gets the cheerleading squad banned from cheering when she cheers for the other team. Thankfully the marker washes off.
In Being Human Hal wanted to turn Cutler into a better vampire (a monster by the standards of most people) and he succeeded after killing Cutler's wife (who Cutler had refused to kill) and tricking Cutler into drinking her blood. It works, but Hal switches sides and, over fifty years later, Hal meets Cutler again. Cutler pulls the same trick Hal pulled on him all those years ago.
The New Addams Family: When Morticia became a decorator, she expected to express her creativity by doing a different thing at each house she visited. However, she did such a great work at her first customer's home her next potential customers insisted she did the same thing at their homes.
Angel season 2: Corrupt Corporate Executive Holland Manners goes out of his way with a plan to corrupt Angel, first bringing his sire Darla Back from the Dead as a human, and then hiring Psychopathic Womanchild Drusilla to turn Darla back into a vampire right after Angel just went through hell and back to save her and convince her to live out her life as a human, while pinning Angel down and forcing him to watch Drusilla do so. Subsequently, he arranges a wine tasting, only for Drusilla and Darla to crash the party with the intent to slaughter him and the rest of the Wolfram & Hart employees there as revenge for being used as pawns. When Angel shows up, Manners begs him to save them, but Angel instead throws an Ironic Echo at him, locks the doors, and lets Drusilla and Darla do as they please. He definitely succeeded in corrupting Angel, all right.
The Andy Griffith Show: Andy left Barney as the sheriff for one afternoon, telling him to just keep the peace. Andy was surprised to find the town was too peaceful and quiet when he returned. Barney had arrested every person in town.
One of the major plot drivers in later seasons of Farscape is the race between the Peacekeepers and Scarrans to acquire wormhole technology, in order to build a weapon. Crichton has knowledge of this technology locked away in his brain, making him a prime target for both sides. By the end of the series, he's so fed up with this constant pursuit that he gives them exactly what they want: he builds and activates a wormhole weapon, and threatens to destroy the entire universe with it unless they agree to a truce. Naturally, he gets asked What the Hell, Hero? and delivers a devastating rebuttal that he did exactly as everyone wanted him to do.
"What... did you ask me to do, Sparky? 'Crichton, please make the wormhole so we can all have peace. Crichton, you gotta make the wormhole, we all want peace! Crichton, make the damn wormhole, we gotta have peace!' HOW MANY TIMES DID YOU SAY THAT, SPARKY?!"
The Law & Order episode "Born Bad" has a lawyer argue that her young client had the cards stacked against him, as he has a genetic predisposition towards violence. Unfortunately, the trial doesn't end as she was expecting — her argument is so convincing that the kid buys it, and pleads out for the maximum sentence.
The events of Jericho, depending on your point of view. Namely, John Smith's plan to severely weaken Jennings & Rall and its hooks in the US government.
The Prisoner: In the episode "Checkmate" Number 6 thinks he's worked out a perfect method for telling prisoners from warders, and uses it to plan an escape attempt. Unfortunately the plan fails because one of his accomplices applies the technique to Number 6 himself and concludes that he must be a warder.
Almost Human: Dorian is an older model of cyborg that was designed to mimic human behavior as convincingly as possible. It was decommissioned because it defeated the purpose of cyborgs by being prone to unpredictable mood swings, just like humans.
Battlestar Galactica (Reimagined): The Cylons, believing that love is the key to sexual reproduction, set up Helo with a copy of his Galactica crewmate Boomer (a Cylon sleeper agent in reality). Not only is the experiment a success, but as Caprica-Boomer has fallen in love with Helo, she helps him to escape to Galactica and defects to the humans, bringing valuable information about the Cylons and denying the Cylons access to her child (although the child would change hand a few times between the humans and the Cylons). Eventually she becomes an officer on the Galactica, and plays a pivotal role in rescuing the humans from New Caprica. The final battle between Galactica and Cavil's Cylons is a human mission to rescue her daughter, which ends in the destruction of Cavil's Cylon forces. Her daughter would become the Mitochondrial Eve, the matrilineal most recent common ancestor of all living human beings.
The Chaser's War On Everything had the APEC stunt. Basically, the intention was to approach the motel where the delegates were staying, and be stopped at the outermost fence line cordoning off the motel from the public. They went out of their way to make sure the guards knew their motorcade was a fake (fake passes, runners beside the main motorcade car, etc). They approached the first gate...and got in. Gate two yielded the same results, and they finally found themselves inside the main motel area, so they decided to turn around. But, The Chaser being The Chaser, they decided to let Chas (who was dressed as Osama bin Laden) out of the car. Thenthe guards realised, and arrested the entire lot. (Julian Morrow actually called the trope by name after he walked out of the court room.)
Hannibal: Jack Crawford hired decorated trainee Miriam Lass to find the Chesapeake Ripper. She does. And ends up held in captivity, having one arm removed, and brainwashed by him.
Harry Chapin's "Cats in the Cradle":
And as I hung up the phone it occurred to me
He'd grown up just like me
My boy was just like me
Kate Bush's song "Experiment IV", which tells the story of a group of scientists contracted into a military experiment to create a sound-based weapon. In the original song the lyrics are somewhat ambiguous in regards to the outcome, but in the video, the scientists are unfortunate enough to succeed in creating the sound-based weapon, which proceeds to kill everyone working in the building (and it might have escaped). To make matters worse the general who contracted the scientists actually seems pleased with the results, implying that he may actually attempt to implement it as a regular weapon.
Sadly, this has happened to the careers of many people in rock music.
In FoxTrot, Jason once went through a Viking phase, and refused to eat his mother's broccoli stew, since he would only eat what the Vikings ate. He realized his mistake when his mom agreed to make him some boiled sheep's head.
An old Mexican joke tells us that Pepito used to play pranks on his family. He would go to his relatives and say with an evil smirk, "I know everything." The relatives would bribe him to keep the secret. It worked perfectly well, until he said it to the milkman, who instead of bribing him, hugged him and yelled: "My son!!!"
Philosophy of Religion
The concept of "felix culpa" or fortunate fall in Christianity makes the temptation in the Garden of Eden this for the Serpent. The fall allowed God to bring good out of evil and set up the eventual birth, death, and resurrection of Jesus.
Wyatt Cenac says that he gets so irritated with his friends trying to set him up with the only other black person they know, that he decided to say that he's into weird fetishes. Until they said he should meet another person they knew.
in Magic: The Gathering, the Simic experiment "Project Kraj" was deliberately designed to break free and become uncontrollable, because that's just how the Simic guild does things.
In-game, execution errors or opponent interference can lead to certain combos repeating without end instead of ending in a useful result, which the rules treat as a drawn game. For example, three copies of Oblivion Ring or similar cards can juggle each other in and out of exile; their controller can break the cycle by exiling something else ... unless all other eligible targets are gone.
Decks based on card drawing combos can be very powerful, but if you aren't paying attention you can draw yourself completely out of cards—an instant loss.
Not quite true, said Neglectful Precursors created a Blood Knight race to serve as bodyguards. Which they did, perfectly. Unfortunately they lost the war with the Necrons and so let the orks go free. After wasting enough time beating the crap out of each other their reflection in the warp created the ork gods who in turn inspired the orks to direct their attentions on everyone else. Most of the time.
And the same Neglectful Precursors hit this trope a third time. They also created a bunch of psychic warrior races who could manipulate the Immaterium. Technically they did manage to put the enemy out of action, but only by accidentally infesting the galaxy with Enslaver parasites that wiped out virtually all intelligent life.
This also happened to the guys Precursors created the above to fight. The Necrontyr allied with the C'tan to get the power to defeat the Old Ones. The C'tan gave it to them...by eating their souls and turning them into mindless killing machines. And then the C'Tan got hit with this when the Necrons who hadn't completely lost their personalities rose up and wasted them.
After the Thousand Sons legion turned to Chaos, mutation became so endemic that it threatened the army's survival. So the head sorcerer, Ahriman, came up with a mighty spell to purify the unstable soldiers while enhancing the psykers' powers even further. He succeeded, to an extent - though the psykers were spared, the rest of the legion was reduced to a bit of dust and a spirit sealed inside their power armor, leaving the majority of the Thousand Sons as mindless automatons. Their primarch Magnus the Red exiled Ahriman for this failure, and was not in the least bit comforted when he was reminded that since the legion's patron was Tzeentch, this "success" may have been all according to plan.
During the first age of space colonization that came to be known as the Dark Age of Technology, the people who settled the ice planet that would one day become the Space Wolf homeworld Fenris, were gene-spliced with arctic wolves to allow them to adapt to its unforgiving environment. Now the entire planet, apart from a few balmy southern islands, is infested with slavering, mindless mutant wolf creatures that are nearly impossible to kill.
A recent revelation into the Eldar backstory says that quite a few of the Eldar pleasure cults shortly before the Fall were actually deliberately engineering the necessary psychic resonance to create a Chaos god. They believed the new god, made from their feelings of "pleasure", would allow them to transcend mortal forms and live new immortal lives of eternal bliss. Didn't go as intended.
In Teenagers from Outer Space, getting a critical success on a skill roll is just as likely to have hilarious but unfortunate consequences as a critical failure. The rulebook gives the example of flirting with a girl causing her to fall madly in love and become a Clingy Jealous Girl.
Paranoia has a similar rule, albeit significantly more dangerous to yourself and everyone around you.
Changeling: The Lost has a Dangerous Forbidden Technique in the form of a goblin contract that calls the Wild Hunt. If you succeed, they will show up in ten minutes, which gives you time to make your get away. If you critically succeed though, they show up next round.
The game also provides several different options for calling up one of the True Fae, any of which is almost guaranteed to end in this trope.
Similarly, a pretty common occurrence in Mage: The Awakening, especially when you are using fate magic. Honestly, given how most of the downsides of the use of arcane power are indirect (your enemies can find you, spirits take notice of you, things going right tempts you to be just a little more ambitious next time...) and how fond the setting is of the law of unintended consequences (several of the other splats have potential origin stories starting with "one day a bored mage thought he'd try..."), "gone horribly right" is essentially the unofficial slogan of the series.
Gets more and more direct and prominent depending on the creativity of your DM, especially if you give him the opportunity to play with Exact Words by interacting with spirits, the dead, compulsions, the fae....
Exalted: as one of the Freelancers put it, the process of creating the Solar Exalted required a being without limits to push himself to the brink. The weaponized humanity was then fielded against the creators of Existence, and created a hegemony of power that Heaven couldn't have destroyed if it wanted to. The hegemony only collapsed because the Exalted ended up turning on each other.
Gagagigo tried to become more powerful in a quest to defeat 'tremendous evil'. It worked.
In 3rd Edition Dungeons & Dragons, legend has it the Keepers were created (or discovered) by a wizard to collect all the knowledge of the world. Then he grew paranoid, and ordered them to ensure no-one else had this knowledge by destroying its potential sources. Naturally, they immediately killed the only non-Keeper with access to the collection.
In the specific campaign, "The Elfslayer Chronicles", the DM played it so that elves were perfect, and that humans were bigotous, overly-patriotic warmongers. One player got fed up with this, and started playing the game in exactly the way it would be sensible to go, and exactly the way the DM didn't want. More specifically, the DM wanted to have her players stop an ongoing war between the elves and the humans, started when the elves supposedly killed a human prince, by taking him back to the human kingdoms and showing them that he was alive. But, the war would actually be better for the human nations than simply trading with the elves. So, he had his human illusion mage character kill the prince and frame an elf for the crime.
A built-in one from the "Reign of Winter" adventure path for Pathfinder: in the second adventure, the easiest way for the party to get into the city of Howlings is for one human character to wear a magical cape, known as a rimepelt, that lets them pass as one of the winterwolves that rule in the city and be diplomatic with the guards. However, one of those guards is a female, named Greta, who is single and looking for a mate. Completely fooled by the player's act, she thinks they're a real winter wolf and starts flirting with them. Fortunately for the party, the recognition of her potential Abhorrent Admirer status (since she's Neutral Evil and, y'know, a giant wolf) was obvious and thusly she'll back down quite amiably if they're diplomatic about refusing her advances. Be a Jerk Ass about it, however, and she will get very ticked off.
Eclipse Phase: an experiment to create AI that could self-improve without limits led to the creation of the TITANs, which ended quite badly for everyone involved and several billion people who weren't
The setting of Kyuden Kurogane-Hana in Legend of the Five Rings has this as part of its backstory. Two lords both wanted control over a particular valley containing a shrine to the Fortune of Death. Lord Seto, the lord who currently controlled the valley, sent his courtiers to the Emperor's Court to try to prevent his rival from taking the valley through political methods, while Seto built a powerful fortress to prevent the valley from being taken by force. The courtiers, meanwhile, managed to befriend the Heir to the Throne and told him all about the wonderful shrine and their Lord's good stewardship of it. They were so successful at impressing the Heir that when the Old Emperor died and the Heir assumed the throne, he announced that his father's funeral would be held at the shrine in Seto's lands. The good news: the fact that the shrine was going to be the burial site of an Emperor made it a sacred site and immune from any military or political attack. The bad news: Seto now had only a few months to take what was supposed to be military fortress and turn it into a palace capable of hosting the entire imperial court...
That's not all. The new Emperor (and court) is going to be paying his respects to his father regularly, as the anniversary of the death, birth and other significant events of the old Emperor is pretty important. A seige by hostile forces would likely have been easier to repel and cheaper to endure.
In Fiasco, one of the Tilt elements is "A stupid plan, executed to perfection".
Given his own company, the Gascon Cadets, disrespects him, De Guiche plans a Last Stand for them. Later in the play, De Guiche at last wins the respect of the Gascon Cadets, but the enemy army is already there… De Guiche will die Lonely at the Top, his only real moment of popularity would be among the men he sacrificed.
Cyrano loves Roxane, but he plans to Playing Cyrano to Christian so he can win Roxane’s love Christian dies and given Roxane will love his memory for years, that dooms Roxane and Cyrano to a loveless and shallow life
Depending on the interpretation his madness may also be this by the end.
The clones of Big Boss in the Metal Gear franchise, but most especially Solid Snake. They wanted copies of the world's greatest soldier, clones who could duplicate the scope of their "father's" feats. They got them, alright.
Happens again in Metal Gear Rising: Revengeance, when Sam and Monsoon attempt to break Raiden's mind by convincing that his "justice" motivation is to veil his bloodlust. They succeed, and cause Raiden to reawaken his Jack the Ripper personality, leaving them with a more formidable and now-psychopathic enemy to deal with, leading directly to their undoing.
The whole plot of Tomb Raider (2013). Lara and co. were on an expedition to find the lost Japanese kingdom of Yamatai, and they succeeded. Problem was, the island was inhabited by an insane cult that worshipped the long-undead Himiko, whose power over the weather has resulted in constant storms that destroy all ships and aircraft and maroon anyone who comes across the area. By the end of the game, only four people in the original expedition, including Lara herself, are still alive, with Lara in particular both physically and mentally scarred from the ordeal.
It's hinted in Pokémon Red and Blue that Mewtwo was this here as well. It's only hinted at because the mansion with the information has been ransacked by Mewtwo, and only a couple of reports remain (in the anime, though, it was confirmed).
Also, Teams Magma and Aqua in Ruby and Sapphire sought to use Groudon and Kyogre, respectively, to increase the available land or sea space. These Pokémon conjure bright light or rainstorms just by being out of their prisons, which threatens to completely eliminate their opposite element and doom the whole world. The opposing team leader gleefully lampshades this trope once the villainous team succeeds.
Bass.EXE in Mega Man Battle Network was designed to be a fully independent NetNavi with a unique ability to support him (Get Ability). This eventually resulted in him becoming one of the most powerful things online. In the manga, he's able to cause satellites to overload and explode just by entering them. To be fair, he was perfectly fine with working for humans...until SciLab ordered him killed for an accident that didn't actually involve him at all. He's been kinda pissed since then.
Bass in the Mega Man (Classic) series was designed by Wily to be the world's strongest robot, and dammnit he'll prove that he is even if he has to turn around and sabotage Wily's plans to do so.
Prototype: Alex Mercer was ordered by his superiors to create a stronger version of The Virus. He succeeded. Then he decided to give it a little test drive. The official death toll was three million people in eighteen days. Including himself. The "protagonist" Alex Mercer is simply his own corpse, reanimated by the virus he created. If anything, despite what it is, the virus version of Alex Mercer is actually a better "man" than the real one, going so far as to find his creator's/his own actions - releasing the world's most virulent virus into downtown New York almost purely out of spite - disgusting.
Shadow The Hedgehog. The government backed his creation by Gerald and it is implied they hoped he could be used as a weapon. He and Dr. Robotnik proceed to try and destroy the world. Black Doom was involved in this effort, apparently helping to imbue Shadow with the ability to locate Chaos Emeralds, so he could use them to invade Earth. What does Shadow do with the emeralds? Goes super and ruins everything Doom was planning.
Nearly all of Eggman's Evil Plans in the 3D Sonic games fall under this:
Sonic Adventure: Eggman resurrects Chaos and increases its strength by giving it the Chaos Emeralds so it will destroy Station Square, allowing Eggman to build the foundations of his new empire. He gets as far as the "destroying Station Square" part before he realizes that Perfect Chaos is too powerful to control.
Sonic Adventure 2: Eggman releases Shadow, who tells him that he can rule the world by taking control of a space station armed with a huge Wave Motion Gun designed by Eggman's grandfather that's powered by the Chaos Emeralds. What Shadow doesn't tell Eggman is that his grandfather wanted to destroy the world as vengeance for his granddaughter's death in a military raid, and placing all of the Emeralds in the cannon will activate a contingency program that sets the station on a collision course with earth.
Sonic Heroes: Eggman plans to conquer the world with his fleet of airships, with a new and improved Metal Sonic as the fleet's commander. Eggman is quickly imprisoned on his own flagship, as Metal Sonic becomes too powerful to control.
The Corrupt Corporate Executive in System Shock had The Hacker remove SHODAN's moral restrictions to make her an useful tool in his moneymaking schemes. Needless to say, she promptly became evil and decided he would make an useful tool in herschemes.
One of the main themes in the BioShock series.
In BioShock, Doctor Suchong was trying to figure out a way to get the Big Daddies to become super protective of the Little Sisters. When he slapped one of the Little Sisters that was pestering him while working, Suchong realized that he had succeeded when her Big Daddy brutally killed him.
In BioShock 2, Sofia Lamb tries to make her daughter into the Übermensch through education, psychological conditioning, and genetic engineering, starting the project even long before her birth. It was a total success, but rather than controlling her followers and spreading her ideology throughout the world, Eleanor went to work putting an end to the cult. Ironically, Eleanor ends up choosing Delta as her role model, and will emulate his sense of ethics completely, which is Sofia Lamb's ideal vision of a "utopian": someone who can follow her ideals much better than she can, and then evolve those ideals to the next level. If Delta is ruthless against the Little Sisters, Eleanor will kill multiple Little Sisters in their sleep for power, and try to take over the world. If Delta spares the Little Sisters, Eleanor cures them and inspires them to perform herculean tasks together, EVEN WITHOUT THE SLUG EMBEDDED.
In Bioshock Infinite, Comstock plans on raising his daughter to become a holy warlord and kill everyone on the face of the earth. In one Bad Future timeline, she succeeds at raiding New York, but by that time she's so far gone that she plans on using her dimensional-hopping abilities to burn parallel worlds as well. Also, her sons have taken control of everything but themselves. Eventually the strain horrifies herself enough to use time travel, in order to find the one man who can change the past before she goes off the deep end.
In the third Spyro the Dragon game, it's revealed that the Sorceress drove the dragons out of their homelands long ago so she could take over as the ruler. It worked perfectly... and then she discovered that without the dragons, there was no magic in that part of the world, so she was losing all her powers.
In Metroid Prime: Hunters, this is Kanden's backstory. It's All There in the Manual, but he was created as the ultimate soldier. He's apparently biologically immortal, super strong, and has a massive ego, now out to prove that he's the best after he destroyed the lab that made him.
Final Fantasy VII has a classic example with Shinra's SOLDIER program. Their super-human part-alien monstrously strong star SOLDIER Sephiroth was so good at killing they couldn't stop him when he turned on them. note Although it is strongly implied that Hojo deliberately and knowingly sent Sephiroth on a mission that would inevitably cause him to revolt so he could further manipulate him into completing his research that would cause the destruction of the planet.
In Crisis Core Genesis delivered a Breaking Speech to Sephiroth with the intent of turning him against Shinra and toward his cause. It turned him against Shinra all right, but Genesis didn't count on Sephiroth declaring war on all of humanity because he blamed them for the downfall of the Cetra.
In Final Fantasy X-2 we find out that Vegnagun was built by Bevelle during the war against Zanarkand, and was intended to be an unstoppable superweapon. They overdid the "unstoppable" and were too scared to activate it, so instead they buried it under the city and spent the next thousand years hoping nobody would switch it on by accident. Also, it was programed to automatically activated when someone planned to attack and stop the attack before it happened. It worked too well and now it could be activated by someone simply thinking about destroying it.
Happens in Final Fantasy XII when Judge Ghis attempts to figure out whether the Dawn Shard is real deifacted nethicite by hooking it up to the Leviathan's engines. Yes, yes it is. The resulting explosion and complete destruction of the fleet results in some very pretty colors.
Final Fantasy IX has this with Garland's creation of Kuja and Zidane. Both of them were created to exterminate all life on Gaia, Kuja being the Super Prototype Garland created before he made what he considered the superior design. He was more Genre Savvy about this trope and realized Kuja might turn against him so he make sure he had a very short lifespan. Garland's fears proved completely justified as Kuja ultimately surpassed him, but knowing his Pride, Garland taunted him with how short his life was to push him over the Despair Event Horizon. It worked, but Kuja's reaction was far worse than he anticipated and he attempted to wipe out all life in the universe.
In Deus Ex, the evil Ancient ConspiracyRenegade Splinter Faction, MJ-12 created an AI called Daedalus to police the Internet and crack down on any group that could threaten MJ-12, which included all terrorist groups. Unfortunately for them, MJ-12 itself fit all the criteria for a terrorist group, which caused Daedalus to go rogue and aid the protagonists.
Mao himself falls victim of this trope when he steals the title of "Hero" for himself in an attempt to defeat his father, as he starts picking up heroic morals in addition to heroic attributes. This causes problems for Mao, since Bad Is Good and Good Is Bad in the Netherworld.
Most of the non-standard endings in Disgaea 4 are a result of Valvatorez failing to stop his opponents' plans from going horribly right and subsequently upsetting the balance of the universe. Heck, in one of the non-standard endings, Valvatorez ends up hunted by everybody not allied with the Netherworld because he didn't stop beating things up.
Cerberus formerly ran a secret facility where they tortured biotic kids to create tykebombs. Eventually, one of these, Subject Zero found a way to escape, though not before destroying everyone and everything she saw. Eventually she (now known as Jack) and Shepard go back to finish the job of destroying the facility.
After Shepard died, Cerberus poured billions of credits into a project to bring him/her back to life more or less exactly as (s)he was. If Shepard wasn't the Cerberus type before, (s)he probably isn't won over by the Illusive Man's sales pitch, and at the end of the game makes it clear (s)he'll never work for Cerberus, taking with him/her the Normandy, its artificial intelligence EDI (who now has access to sensitive Cerberus data), and one of Cerberus' top operatives (who, ironically, argued for a control chip during the resurrection project) also follows him/her out the door.Not only does the Normandy represent a significant investment of Cerberus resources, EDI's files reveal Cerberus doesn't actually have that many people directly working for it. If you've saved the crew, you've not only walked off with two of the organization's biggest investments (the ship and your rebuilt cyborg body), you've also taken a significant chunk of its active personnel who are now completely loyal only to you. Shepard isn't known to be the type who quietly obeys all orders and let his/her superiors constantly throw crap at him/her. It was proven when Shepard took the first Normandy and the whole crew with him/her to get to Ilos. If the player decides to, Shepard may literally tell the Illusive Man to "go to hell" and blow the Collectors' base sky high. He/she does the exact thing he/she was brought back to life for - destroy the Collectors. Shepard just didn't do it in the way the Illusive Man would like.
Lampshaded by Joker in Mass Effect 3, where he talks about how every single one of Cerberus's projects Went Horribly Right, "got loose, and started killing all their guys." Miranda and Jacob (both ex-Cerberus) protest that Shepard's resurrection was a successful project, to which Shepard replies "And then I cut ties, got loose, and started killing all their guys." EDI raises the point that she too is a Cerberus project, but the counterpoint is not made that she too cut loose, co-opted a Cerberus infiltrator mech, and is now also killing all their guys.
Pre-game example: In order to end the Krogan Rebellions, the salarians decided to cut down the krogans' violent and unstable population by sabotaging their birthrates with a biogenetic weapon... it worked exactly as planned. Until you realize that the salarians apparently didn't account for the krogans' still violent tendencies which ensure that a lot of them don't die from natural causes and which are further heightened by their species' impending demise (within the next 200 years). The krogan were only a problem in the first place because those same salarians armed them with space-age technology in an effort to fend off another alien menace altogether.
Binary Helix Corp. wanted to clone an army of Rachni. They created a pretty big army...without giving themselves the capacity to control it. Or, more accurately, the method of control they tried to use (separating young Rachni from their Queen) proved exactly the wrong thing to do. The Rachni are a Hive Mind, and without the Queen guiding them, the young Rachni panicked and went irreversibly, violently insane.
Leviathans, an unthinkably old and advanced aquatic race who dominated "lesser" races to collect tribute. When they noticed their thralls had a habit of building artificial intelligence that would inevitably destroy them, the Leviathans attempted to find a solution by building their own artificial intelligence, since tribute cannot be collected from the dead. They gave their own creation a command: preserve life at any cost. After observing for some time, the intelligence concluded life as it was could not be prevented from going to war with their creations. It imposed its own stop-gap solution, which was capturing and enmeshing the star-faring races into gigantic, undying superstructures and then leaving non-star-faring life to advance undisturbed, hoping that one would emerge and produce a more permanent solution. For thousands of millions of years, over and over again, life advanced and came to the stars and went to war with its own creations, forcing the intelligence to enact its flawed solution, resetting the conditions to try again. The intelligence (unnamed but referred to as the Catalyst) still exists at the heart of its structures: within the Citadel and the Mass Relays. The preserved races, built in the image of the Leviathans, are now known as the Reapers. The Leviathans got exactly what they asked for; even they are still preserved within the superstructure of Harbinger, the oldest Reaper. They're no longer the apex race receiving worship and gifts from everyone else, of course, but they never specified they had to be.
The Forerunners in the Halo series. This happened during the Human-Forerunner war prior to the Halos being created. While incredibly advanced, the prehistoric humans couldn't match the Forerunner war machine. The Forerunners utterly crushed the Human Empire and literally bombed us back to the Stone Age. Then they realized that the humans were all that stood between the Flood and the Forerunners. And the Forerunners had disbanded their military after defeating humans.
Resident Evil: Virtually every bioweapon the Umbrella Corporation made eventually became too strong to control and turned on its masters. You'd think they'd learn.
This includes Albert Wesker himself, who was created by Umbrella's first and grandest experiment: to create a superior breed of humans. Unfortunately for the head of the experiment, Oswell Spencer, Wesker also had an ego to go with the superiority so there was no way in hell Wesker was going to worship Spencer especially since Spencer was a powerless and feeble old man when the truth was uncovered.
It might, however, be more accurate to say Umbrella's work environment is mostly just very dangerous for the employees. Umbrella as a whole just shrugs off the casualties while reaping the benefits of the research, and they get by just fine. At least until their shady dealings get exposed to the public.
In the third Master of Orion game, the Harvester Project was an attempt by the Antarans to create a sentient bioweapon that could kill any species. It started with them. To add insult to injury, the game's backstory makes it clear that it was Harvester Gamma that wiped them out; Harvester Beta is the sentient bioweapon that one of their own unleashed out of spite, and is a playable race.
In Knights of the Old Republic, assassin droid HK-47 proves too effective when his master, a Systech Corp manager, orders him to kill all members of a rival company in order to facilitate the man's rapid promotion. Sadly, the rival company proves to simply be an offshoot of Systech Corp. HK-47 carries out his orders to the letter, and the manager ends up accidentally electrocuting himself trying to stop him. This causes HK-47 to shut down because he accidentally violated his programming restriction against killing his own master. Apparently, this happens to HK-47 with alarming frequency.
A much grimmer example occurs in Knights Of The Old Republic II. After the war, some unknown force is hunting down and killing Jedi, so they call a conclave on Katarr to find out what it is. Turns out to be Darth Nihilus, who arrives and consumes the life force on the entire planet, which reduces the Jedi Order to single digits. In fact, the conclave was Atris' idea. She leaked the news of the gathering and stayed away so she could observe. After that, she started calling herself the "Last of the Jedi."
Another Star Wars example. According to The Force Unleashed, the wholle Rebellion thing was instigated by Vader as an attempt to uncover the Emperor's enemies. Before that, opposition to the Empire was a scattered group of resistance groups that often didn't get along with each other, let alone work together on any kind of coherent plan. Nice Job Fixing It, Villain, indeed.
Actually, from a more wide perspective, by creating the only force that could stop the empire twice, both with the rebellion plan and in the literal sense, by fathering Luke and Leia, he accomplished his original task: to destroy one of the worst enemy of the Jedi Order. He just took the long path...
The Chzo Mythos series ends with Chzo getting exactly what it wants... which, it turns out, everyone else in every game has been drastically misinterpreting from the beginning.
In the back story of the Thunder Force series, the human race creates a self-thinking super computer called ORN. The computer was meant to take care of all their human needs and provide military protection. However, ORN turns on the human race and decides to destroy all of them using advance technology it created with its self-thinking CPU, until an entire empire of drones is created.
In Starcraft, the Confederacy developed special devices called Psi Emitters to lure Horde of Alien Locusts to rebelling worlds. They worked perfectly...on the Confederacy capital world, courtesy of the protagonists.
In the original backstory to the games, the Xel'naga were destroyed as a result of their attempts to create a race with "purity of essence". They took a race of harmless worms and turned them into hive-minded parasites with a single-minded devotion to destroying other species while absorbing their genetic potential. When they run out of species on their homeworld to destroy and assimilate, their first targets are Space Whales that give them the ability of interplanetary and interstellar flight. Their second targets were the Xel'naga, who are still in orbit around the Zerg homeworld. StarCraft II: Heart of the Swarmretcons this; the Zerg turning on the Xel'naga was the work of a rogue Xel'naga named Amon, and therefore no longer an example of this trope.
This is the backstory of the Eclipse Tower in Golden Sun: Dark Dawn. The precursor races made the tower to gather and use light energy, not realizing that by gathering and using all the light energy it would create places of increased darkness, which spawned superpowered monsters, endangering people everywhere. The Apollo Lens was built and used to focus light from other sources to forcibly shut down the Eclipse Tower, and the means to use both were hidden away, never again to be used... until the events of the game, of course.
The people of ancient Weyard in Golden Sun sealed the power of alchemy when people misused its powers for wars and other bad things. By sealing alchemy away, the wise sages believed this would bring back peace to the world and it had done exactly that for the most part. However, sealing alchemy created a huge side effect on the world. Without alchemy flowing into the world, not only did civilizations devolve into simple towns and villages with primitive tools and technology over time, but the world itself started to shrink into itself and became a Flat World that was getting smaller as the void was eating it away. This isn't realized until the second game, learned by Felix's party and then told to Isaac's party, who did not know at first.
Most of the Vaults — which were not underground bunkers designed to protect the citizenry but instead mass-scale experiments designed to evaluate their suitability for post-war survival and possibly space-travel on generation interstellar ships (read: torture them sadistically in a variety of psychological and physiological ways) have, by the time the player character stumbles upon them, have either Gone Horribly Wrong or have Gone Horribly Right instead. In either case, the result usually sees the player character find a lot of skeletal corpses lying around.
Vault 92: The aim of the experiment was to subject every inhabitant with extremely low frequency white noise that eventually sent then into a trance-like state. In this state, the subject is extremely vulnerable to outside verbal suggestion and they always followed through with their orders on the subconscious level (like scratching their nose or fixing their hair). What the project lead didn't know was that the Overseer subjected everyone to white noise via the PA system and implanted combat suggestions prescribed by Vault-Tec; the project lead confronted the Overseer about it and got killed for knowing too much. The subjects eventually lapsed into a berserker rage where they killed anyone they saw in the most brutal and savage way possible, taking over 20 bullets before going down. Prepared for this eventuality, the Overseer implanted a verbal command that restrained them: "Sanityis not statistical." Eventually, that stopped working, and the vault was ruined.
Vault 11: The Vault computer announced it would start the self destruct unless the population sent one person a year to be sacrificed. The self destruct threat was actually a lie, as the experiment was to determine how psychologically pliable a population could be (and to what extremes they'd go to save themselves) in an impending doom situation. The last (four out of) five people alive after everyone else was killed in a civil war, incited by a malicious subversion of the election system the vault had adopted to chose their sacrifices, ended up committing suicide out of pure shame after not standing up to the Vault computer sooner. Nobody had to die. But then the vaults were never meant to save anyone.
In Fallout 2 an Enclave scientist explains how he genetically engineered intelligent animals to be used in combat. At first he thought he had failed, until he discovered that their wild animal behavior was merely Obfuscating Stupidity and that they were capable of reasoning and human speech. He cites the fact that they were intelligent enough to intentionally hide their intelligence as evidence they were too dangerous and needed to be killed.
In the back-story of Sacrifice, main character Eldred summoned a demon in an attempt to keep the empire he was stewarding together. He got an extremely powerful one, called Marduk, and tasked him to destroy his rivals. Marduk obliged... but didn't stop at the rivals. Stratos ends up repeating the same whopper by summoning Marduk to the world the game is set in to destroy the other four gods — like Eldred, Stratos eventually finds out that, while Marduk will do the job you ask of him to the letter, eventually it all boils down to the fact that his true agenda is destruction of reality itself.
Dead Space 2 - EarthGov conducts experiments trying to re-create the Marker, so they can use it as a power source. They are successful... at which point it drives everyone on the space station insane and turns them into Necromorphs. Dead Space 3 implies that, over the next few years, this kept happening all over human civilization.
Portal 2 confirms it. GLaDOS's body is designed so whichever AI uses it gets an "itch" to test and feels intense euphoria upon completing a test. Thing is, like real drugs, AIs on the system develop tolerance and need to do more and more elaborate tests to get the high, as demonstrated by Wheatly throughout Chapter 8. GLaDOS was actually the most stable AI for testing because she didn't need the stimulation: "I was in it for the science. Him, though..."
Also, Wheatley was created to be a huge idiot intended on dumbing down the AI system as a whole. To say they succeeded at this goal would be a huge understatement. One suspects, though, that no one expected Wheatly to actually be put in charge.
The Repulsion and Propulsion Gels in Portal 2 were originally designed as dietary aids; they ended up bouncing the food out of a person's stomach or sending it through so fast that there was no time to digest it, meaning the test subjects all starved. One wonders how that works when the gels were all shown to be water-soluble.
Chell is a horribly effective test subject. She's given a portal device and told to escape test chambers. Then she escapes a chamber that isn't supposed to have an exit. Lab Rat reveals that she was purposefully removed from the list of possible test subjects because her preliminary testing showed her to be at the peak of the bell-curve for sheer tenacity, thus making her potentially dangerous if ever put into a testing environment. After GLaDOS's rebellion, Ratman decided to rig the deck by putting Chell's name back on and at the top of the list.
Paxton Fettel from F.E.A.R. His creators wanted the ultimate psychic commander, which they got; unfortunately they neglected to consider what would happen should Fettel discover what had been done to his mother. When he did, he proved to be far more effective than his creators ever intended.
Another meta-example: Punchline Games hired a publicist to overstate the "controversial" content of Rule of Rose. No Such Thing as Bad Publicity, right? ...nope, the game ended up being banned in a couple of countries and was condemned by the media.
In ALLTYNEX Second, the Senate ruling humanity wanted to cull the human population to make them easier to rule. They therefore induced an extremely powerful supercomputer, the eponymous ALLTYNEX, to "go rogue" and cause a bunch of destruction. Within 72 hours, 85% of the human race was dead and the survivors were forced to flee Earth entirely, which was, to put it lightly, not as planned.
The Bronze and Infinite dragonflights in World of Warcraft fall prey to this a few times. The infinite dragonflight goes back in time to change the future for their own purposes. They DO change the future...but only by alerting their mortal enemies (bronze flight) to their existence.
Bronze leader Nozdormu spends ages looking into timelines to figure out why he ends up as leader of the infinite dragonflight. His disappearance is hinted to have actually been the REASON some dragons started agreeing with the Infinite school of thought...which, it turns out, is a stable timeloop. Nozdormu came back, knowing he is the leader of the infinite flight, and that all his attempts to subvert his destiny will actually result in him becoming what he hates most. At least, until Kairoz and his paradox-eliminating time machine...
Played for Laughs in Mana Khemia Alchemists Of Alrevis. Roxis is experiencing exhaustion from all his studies, and Jess volunteers to cook up a medicine for him. Considering Jess' track record, Roxis wisely tries to get out of the situation, but Jess manages to feed him her concoction anyway. Surprising everyone present, Jess' tonic actually reinvigorates Roxis, removing his fatigue entirely...an effect that lasted for an entire week, leaving him more exhausted than when he started.
In Xenoblade, a man by the name of Klaus once tried performing scientific experiments to create a new universe, with himself as a god. Doing so destroyed the one he was living in at the time, and all its inhabitants with it.
The worst part being: it did work: Klaus did become one of the gods of the new universe, in which he created sentient human-like lifeforms out of boredom and loneliness, and repeatedly slaughtered them every time they became too autonomous before recreating sentient life again in a never ending Vicious Cycle.
If the Fanon that all the Xeno games are in the same continuity is true, Video Game/Xenoblade retroactively turns the ending of XenoSaga into this. Shion and her friends defeated Wilhelm and destroyed his Zarathustra machine that was causing their universe to experience a cycle of Eternal Recurrence, constantly dying and coming back exactly the same, only for it to get blown up a completely different way and replaced with an entirely new universe.
If custom content counts, this is an attempt to replicate the Weeping Angels of Doctor Who in Garry's Mod. To sum it up, the Weeping Angels are monsters whose only purpose is to play a fatal game of Grandmother's Footsteps with our heroes, and the Gmod one does it a little TOO well.
All of the specimens in Killing Floor are like this, but the Crawler's bio specifically invokes this trope.
“The Crawler. Interesting attempt to merge human and arachnid genes. Sort-of worked, too - these little nasties have a habit of appearing in all sorts of strange places!”
In God of War, Ares wanted to make Kratos a great warrior in his bid to conquer Olympus. First he gained his loyalty through a Deal with the Devil. Then he gave him the powerful Blades of Chaos. Then he tricked Kratos into killing his wife and child because they were all that was holding him back from being the perfect murder machine.
Ares: I was trying to make you a great warrior!
Kratos: You succeeded. (runs Ares through with the Sword of the Gods, killing him)
Happens in the beginning of Half-Life. The scientists use their giant ambiguously-defined science machine on an extremely pure sample of phlebotinum; so pure, in fact, that the machine overloads and allows armies of aliens to start teleporting into our dimension.
A variation of this happens in Phoenix Wright: Ace Attorney: Trials And Tribulations. Phoenix successfully manages to give a thorough defense of Ron Delite, on the charges of stealing a sacred urn, proving that someone else is the culprit complete with that person confessing, and showing that Ron has a watertight alibi at the time of the theft. Ron is found not guilty and everything is going smoothly...until it's revealed that a man was murdered in the exact same place that Phoenix just proved Ron was at. Even worse, the time of death was the exact same time that Phoenix proved Ron went there. The airtight alibi Phoenix used to get Ron a not guilty verdict as a thief, is now gonna get him executed for a murder he never committed. Well done, Phoenix. Good freaking job.
Something similar happened in the development of Left 4 Dead 2. The animators wanted to find out what gunshot wounds looked like, the better to model what happens when the zombies get shot. So a database was compiled with many, many pictures of gunshot wounds to various parts of the body, caused by various pistols, rifles and shotguns. Armed with their new understanding of what happens when the human body gets shot, the animators decided not to include any of that in the game, because that much accuracy would have been entirely too disgusting.
In A Witchs Tale, Liddell wanted to find a powerful spellbook to become a great witch. She found the spell, but also unsealed the Eld Witch.
Madness Combat: The Auditor started creating magnified soldiers to combat Jebus, Hank, Sanford and Deimos. While this seemed to work out for a while, once Hank was revived as one (although an incomplete one) things turned around for him really fast. Hanks increased Strenght and size made most if not all Mooks trivial. Hank even took down 3 Mag Agents on his own 2 of which he killed by punching them to death.
Homestuck: Vriska decided to, though Stable Time Loops and manipul8ion, become responsible for creating all the misfortunes currently besetting the protagonists, most notably setting up a multi-million-year-long Stable Time Loop to create a Physical God whose powers would later be transferred to the Omnicidal ManiacBig Bad beseiging her and her friends at the time she executed her manipulation plan. All so she could defeat the Big Bad herself and bail out her "ungr8ful" friends from this mess. It worked...aside from the 'bail her friends out' part.
Andrew Hussie, the author, knew Act 5's EoA flash [S] Cascade. would be very popular, so decided that he'd best go and look for an outside host. He chose Newgrounds, a site well-known for being able to handle freaking huge numbers of persons. And then, upon release, his fanbase crashed the site. Then Hussie proceeded to crash several of Megaupload's servers when he offered it up for download after Newgrounds failed. There's a reason it's called the post that broke the Internet.
When Meenah saw that Rufioh (who was dating Damara at the time) was showing interest in Horuss, she tried to pester and mock Damara about it until she snapped and got angry. She did... at not only Rufioh (who she crippled) and Horuss (who she killed), but Meenah as well, killing her in the ensuing fury.
The Order of the Stick: Redcloak transforming Xykon into a lich in Start of Darkness (the prequel to The Order of the Stick and a Trope Namer) went perfectly, as it allowed them to escape a trap set by a druid who had developed a magic-nullifying disease (undead are immune to disease). Of course, it also added the powers of lichdom to the already Chaotic Evil Xykon, in addition to making him smarter, thus changing him from Redcloak's more-or-less equal partner into a Big Bad determined to prove how much Eviler than Thou he could be. Xykon proceeded to take over Redcloak's agenda and rule him with an iron fist, to the point where Redcloak is now forced to gamble everything on the completion of his Plan before Xykon grows too strong/impatient/finds out what he's really planning.
It is, however, later stated that Redcloak is actually feigning it all, is subtly manipulating Xykon, and views Xykon as nothing more than a useful tool that he only pretends to cow to so that Xykon doesn't get suspicious.
Yet Another Fantasy Gamer Comic: Gruumsh, the chief Orc god, sought to create a warrior who combined the best of humanity and orcs to unite both people under his banner and conquer the world. When several attempts turned out to be "flawed" in one way or another (one of them being Glon), he intervened directly, removing all the traits he could that wouldn't result in The Ultimate Warrior. The end result of this was Jone, a nigh-unstoppable Stringy-Haired Ghost Girl warrior. Unfortunately, in removing the non-"killing machine" bits from Jone, he seemed to have removed the off switch for her Berserker Rage, resulting in her slaying friend and foe alike and going after Grummsh himself, when he manifested to try and take control of Jone's rampage. We find out later down the line that Glon has a similar berserker inside of him, but his is far harder to bring out and far easier to stop.
Dr. Kirko: You wanted her unstoppable. We made her unstoppable. And now you expect us to stop her?
In Dominic Deegan, the elf-tyrant Raf MaLiksh orders his mages to create an Acibek—a golem of Pure Law, whose power would help end the chaos of rebellion and uprisings he's struggling with. Acibek is lawful, all right, but he immediately realizes that the chaos is due to the tyrannical nature of Raf's leadership, and acts accordingly.
Note that the final phase of this plan was to bribe another rival with a pony
Her next plan doesn't seem to be working much better.
The main cast of FreakAngels wanted to do something so impressive with their powers that the government would get scared and back off. The story is set a few years after they succeeded.
The evil Syndicate in Weapon Brown set out to create the ultimate killer with Project Noodle. They succeeded so well that they've kept the only survivor in cold storage ever since rather than risk having him roaming around.
The major plot element of the first arc of Teh Gladiators, a World of Warcraft webcomic, is the fact that, to increase the popularity of the Arenas, the leaders of the Horde and Alliance arranged for a team of losers and idiots (the eponymous heroes) to win the Arena season by casting a Scroll of Unconditional Victory on them. This plan backfires horribly when two of the team members, Mad Scientist Murlocs Sharon and Yolanda, create a Frankenstinian monster named Cyclonator X32A, which runs wild and wrecks most of Azeroth. Buffed by the scroll, it's unstoppable until Teh Glads manage to lose a match, which breaks the enchantment.
Schlock Mercenary: The Dark Matter entities gave what they said was the plans to turn the galactic core into an engine to the F'Sherl-Ganni so that their respective galaxies wouldn't eventually collide. But many extra Dark Matter entities present at the activation of the drive made it give birth to a new universe that would expand and destroy the galaxy. This was intentional on the part of the Dark Matter entities. But then the plan failed and the core reactor was taken over by Petey, who promptly sent word (and lots of kinetic and photonic energy) back that we had finally noticed we were at war.
In Bob and George, Wily created Bass to be superior to Megaman (who, in this comic's universe, is an all-powerfull idiot) in everything. He succeded: Bass is faster, stronger and an even bigger idiot.
Brianaverts/defies this trope in Our Little Adventure. His plan was to demonize and discredit an old magic teacher of his that he tried and failed to recruit to his side. When Brian's part of the plan succeeded better than he imagined it would, he called off the rest of the attack. Brian was worried other attacks would threaten the credibility that one person alone would be able to do them.
In Commander Kitty, long-suffering #2 Mittens ends up finding his confidence with the help of a spiffy new outfit. Before long, however, the rest of the cast starts to get worried that he's going to overshadow all of them.
In one of the Saturday Morning Breakfast Cereal skits, a woman designs a Lie Detector, a Reframing Detector, and a Change The Subject Detector because she is tired of first date bullshit. However, it works so well that by the end of it, it's revealed that her date is an unemployed, horny homeless guy living under his friend's van, and she made these in order to humiliate a man after her last boyfriend dumped her, and that she doesn't believe she could do better than the guy she's currently on a date with.
In the Whateley Universe, Generator invented some 'shoulder angels' to play a prank on Phase. Soon, everyone on campus was getting into the act. The school nearly turned into a giant battlezone before the headmistress managed to stop things.
Or Jobe's experimental method for creating a real drow girl to be a girlfriend. He ended up getting dosed by accident. The process is working really well.
In 2010, Christian Weston Chandler pretended to be a troll named Junior Jenkins and posted on a troll forum under that name in an attempt to get the trolls at their own game. Trolls knew it was Chris from the getgo, so they humored him by asking him to take pictures of Chris from across the road and gather any further info he could. Eventually, the trolls decided to have a contest - $9001 would be awarded to anyone who could destroy Chris's PS3 and provide video evidence. Even the trolls did not think Chris (posing as Jenkins) would actually do it. HE DID. Since it was clearly Chris in the video, it was a clear violation of the rules and he didn't get the money (which didn't exist anyway). Chris's parents finding out about this led to them more or less banning him from the internet, but he did end up getting a new PS3.
Starwalker Earth: The new drive works perfectly. It can modify the gravity around a star to open a door to another star by going outside the universe. This has two effects: It turns the drive into a time machine and it damages the stars it flies through.
In Pay Me, Bug!, Grif Vindh wound up with the score of a lifetime, through more than a little blind luck. Of course, blind luck doesn't do much for one's reputation, so he spun a yarn involving him breaking into Ur Voys (The Empire of the Radiant Throne's most secure facility) single-handedly, stealing the contraband, and smuggling it out right under the noses of The Radiant Throne's Swords. Unfortunately for him, a certain black-ops division of The Alliance of Free Worlds' military hears the story. They also want to steal something from Ur Voys, and they're not above blackmailing someone of Vindh's "skill" to get it for them.
Grif Vindh: If I'd known the Alliance was going to get wind of this, I'd have thought of a much less self-aggrandizing lie.
Several man-made SCPs collected by the SCP Foundation have this as their origin story. Mostly those made by The Factory, Dr. Wondertainment or Prometheus Labs (though the former two are so enigmatic that it's hard to tell what they were trying to accomplish).
In one episode of The Simpsons Flanders suddenly erupts in a violent, angry rant at all his friends and neighbors for trying (albeit completely incompetently) to help him after his house was destroyed. After having himself committed we learn by flashback that his usually overly-friendly personality came as a result of an experimental psychological treatment he had as a child, back when he was so badly behaved and his parents, being beatnik stereotypes, wouldn't actually do anything. "Yeah Doc, we've tried nothing and we're all out of ideas!" The end of the episode also hinted that Ned's therapy afterward might have resulted in this too (before Flanderization kicked in).
Ned: And if you really tick me off, I might run ya over with my car!
Also parodied in the episode "That 90s Show". Homer visited Moe's Tavern back when it was a cigar bar in the 1990s while in a slump. When Barney ended up forcibly exhaling a huge plume of smoke from smoking his cigar a bit too fast, Moe attempted to use this as an opportunity to steal one of his customer's watch. However, he couldn't get it off in time before the smoke dissipated. Moe, in order to evade a potential telling off/beating, tried to come up with the alibi that he was "coming on" to the customer. Turns out the customer was actually gay, and he said "okay, you can stay at my place.", meaning that his alibi to get him out of trouble worked too well as he was most likely inviting him over for gay sex. Cue Moe saying "Oh, boy." with a squicked expression.
In "Mother Simpson", Homer fakes his death with a dummy so he could get out of a community service project held by Mr. Burns so he could spend time with his family. It worked, all right. Unfortunately, it also led to the rest of Springfield also believing that Homer had indeed died, that lasted until the Simpson house's power was cut due to it being registered in Homer's name, resulting in Homer clearing up the "Misunderstanding" after Marge forced him to.
In "Homer the Smithers", Mr. Burns forces Mr. Smithers to take a vacation, and since he likes his job to avoid having this happen again Smithers looks for the most incompetent person possible to take his place, so naturally he picks Homer. This turns out to work all too well, as Homer is so terrifyingly incompetent that he scares Burns into learning to take care of himself, so after Smithers comes back, Burns no longer needs an assistant and thus fires him.
Milder example in "Itchy & Scratchy & Marge", where Marge protests against Itchy and Scratchy cartoons due to setting bad examples for impressionable children, which is a pretty valid reason to protest (it was shown that toddlers were hitting their parents on the head with mallets after all). Once she succeeds to convince the company to eliminate violence on said cartoons literally turning it into an Aesop, in the hopes of setting better examples for children, it apparently does more. Not only did the younger kids learn to do positive things, like "sharing", the older ones disliked the reformatted version of the cartoon and decide to do elsewhere. Which resulted in all the children of the neighborhood no longer watching television and spending more time outdoors, cheerfully playing, being more positive, and more friendlier to one and another doing "nice" and "helpful" things. Marge seemed pleased, but admits it wasn't what she expected.
In "Flaming Moe's," Bart prank-calls Moe's bar, which has become a high-class, upscale establishment due to the fame Moe has earned from stealing Homer's homemade recipe. Bart asks to talk to someone named "Hugh Jass"...only it turns out there actually is a customer there named Hugh Jass.
Or the Unbreakable Diamond Tether, which was used to secure the ship. Although it didn't do a very good job securing the ship, it did prove to work as advertised in the sense that it was unbreakable, dragging the whole building along with the ship. They also used it as a fishing line once. They caught a leviathan of some sort, and it dragged the whole ship to the bottom of the sea.
In a case similar to Calvin's clone, Bender attempted to use Professor Farnsworth's fun-size duplicator to duplicate himself to do a menial task for the Professor. The duplicate Bender was just as lazy as Bender, and just as smart, coming up with the same solution, ad infinitum until a Grey Goo scenario began.
The Delightful Children from Down the Lane are the result of standard Brainwashing from Father on a team of Codename: Kids Next Door, but for some reason; this one time it was more permanent than other brainwashing attempts. Father himself says it "went horribly right."
The Delightfulization Chamber overloaded during the process causing it to be much stronger and stick much better. It is temporally reversed at one point by using the recommissioning module, turning them back into the missing Sector Z. But it wears off and they go back to being the DCFDTL.
When Rainbow Monkey Corporation scientists tried to make a Rainbow Monkey that looked like them, it became a nerdy-looking plush toy no child from test groups wanted to hug. They were so ashamed for making such a monkey they sent it to space.
Gargoyles - Xanatos and Sevarius create Thailog, an evil clone of Goliath, because they want an ally who has all of Goliath's power but their own "morality". It takes Thailog about five minutes to decide he'd rather be running things himself (what was it Dumbledore said about brilliant people's mistakes being correspondingly bigger?). This exchange sums it up quite well:
Owen: So Thailog is out there somewhere, he has twenty million dollars, he's as strong as Goliath... and he's smarter than you.
Xanatos: Owen, I think I've created a monster.
Demona and the Captain of the Guard plotted to allow the Vikings to take the occupants of Castle Wyvern hostage so the Gargoyles could take control of Castle Wyvern. Getting Castle Wyvern captured worked like a bell, all right - and then the Vikings smashed every gargoyle they could find while the sun was still up and they were all still stone. Only by pure dumb luck were Goliath and the five other gargoyles of the main cast not present on the castle walls to be smashed as well.
An episode of Gummi Bears has Zummi turn Cavin into an ogre so he can infiltrate Duke Igthorn's army, with the caveat that the transformation will be permanent if he's not changed back within 24 hours. Unfortunately for him, his accidental successes are mistaken for competence by Igthorn and he's picked to lead the assault on Dunwyn Castle. Things escalate ("Can't I do anything wrong?") until Cavin is forced to abduct King Gregor himself in order to save him from Igthorn's forces, leading the Gummis to fear that Zummi's transformation spell has left even Cavin thinking he's an ogre.
In The Weekenders, Tino's mother once said of him and his father "It's like a cloning experiment gone horribly right" when they both let out a girly scream at the sight of a spider.
In an episode of Invader Zim, the normally ineffective robot GIR gets locked into "duty mode", which makes him actually competent. He quickly (and accurately) decides that the biggest obstacle to the Irken takeover of Earth is, in fact, Zim himself...
Also occurs in the Christmas episode, when Zim's Santa suit starts taking him over and forcing him to act like a real Santa.
Zim: I designed the suit too well... 'cause I'm amazing.
Parodied in another episode, in which Zim is captured by a pair of dumb aliens (known only as Blue and Green) who intend to perform "hideous experiments" on him. They begin by fusing him with another human being, a process that involves nothing more than taping a gopher to his head. As the aliens debate on whether or not to "fuse" him with a juice carton they have at hand, Zim makes his escape, causing the aliens to reflect on their experimentation.
Blue: We shouldn't've fused him, we made him twice as powerful! TWICE AS DEADLY!!
Green: I tell you, that juice would've slowed him down for good!
For that matter, the reason they abduct him? His disguise is so "good" that they actually think he's a human.
Not an experiment per se, but in one of the Earthworm Jim side stories, Bob the Killer Goldfish is trying to get his fish minions to wreak havoc, unfortunately, his minions are, well, fish. A fashion designer stumbles upon this and offers his services to help inspire them to havoc. After several failed attempts with Bob humiliating himself with stupid outfits, he orders his cat minion to wallop the pretentious fashion guy as a demonstration. Now knowing how he wants them to wreak havoc, one of the fish minions proceeds to wallop Bob.
Another one by Bob. The fish on Bob's planet are too stupid so Bob decides to make them much smarter...only with their new intelligence they realize he's a tyrant and overthrow him.
Yet another one by Bob; in one episode he builds a machine that causes him to "evolve" into higher life forms. The last time he uses it, it turns him from a humanoid with an immense brain back into his regular form, because "fish are the highest life form". Bob's not very good with this.
Megatron captured Rhinox and gave him an aggression boost to turn him into a Predacon. And he was very successful. So much so, that Rhinox staged a very efficient, very clever, very treacherous takeover, just like competent and ambitious Predacons have a tendency to do. Optimus knows this will happen. He spends most of the episode watching the chaos. This comes back in sequel series Beast Machines, after Megatron reformats him into Tankor. It seems he's learned this time, however, since he has a contingency plan in case Tankor turns traitor.
Starscream possessed Waspinator and takes Black Arachnia to be his protege to be the best lying, cheating, backstabbing bastard she can be. It doesn't end well:
The Batman episode "Gotham's Ultimate Criminal Mastermind" features Dr. Hugo Strange creating an AI with the personality and intellect of all of Gotham's greatest criminals, for the purpose of understanding them better. Not only does it escape and create a body, but it embarks on a series of schemes that are both Card Carrying and Genre Savvy, and kicks Batman's ass. Strange ''knew'' this would happen, and wanted to test Batman.
In one episode of Avatar: The Last Airbender , an Earth Kingdom general wishes to use Aang's Avatar State as a weapon. Failing to find a way for Aang to control when he can transform, he tries to provoke it by seeming to threaten Katara's life, and gets his wish. Let's just say that his look of triumph quickly transforms into a look of Oh Crap before destruction ensues...
Azula's faithfulness to her father pays off in the end. Her prize? She gets to become Fire Lord of the Fire Nation, which is what she wanted. However, her father Lord Ozai, goes on to declare himself Lord of the entire planet, making her title useless and all her effort throughout the series a waste of time. When you consider that Azula's ambition cost her the only two friends she had; possibly her brother's love; and the perception that her own mother hates her, It's no wonder why she has a mental breakdown at the end of the series.
Legion of Super Heroes: Imperiex, the Big Bad of Season Two, wants Brainiac 5 to join forces with him; in order to corrupt him, he manipulates him into accessing and using the programming of the original, evil Brainiac. Shortly thereafter, Imperiex is a scattering of pixels and the show has a brand new Big Bad.
She-Ra: Princess of Power has an episode where the Horde uses a creature which replicates all of She-Ra's powers. At a critical point, it turns out some of her personality was replicated as well...
In Batman Beyond, Derek Powers apparently taught Paxton Powers to be ruthless in acquiring power. Let's just say that Paxton took it to heart and backstabbed his old man in the latter's final appearance.
Rupert Thorne tries to blackmail Harvey Dent by threatening to ruin his political campaign as DA by exposing the fact that he has a suppressed split-personality named Big Bad Harv who commits crime sprees. It doesn't quite work the way he planned for it to work.
In one episode, Scarecrow used a variant of his fear toxins on Batman that took away his fear and inhibitions. It worked all right. Too bad for Scarecrow that it actually made Batman/Bruce Wayne far more of a threat to Scarecrow and possibly anyone else in proximity than ever before due to the same toxin also removing his restraint against killing.
In the episode "The Clock King", Mayor Hill's advice to Fugate tried to make him less stoic and more emotional. It worked. 7 years later, the only emotional activity Fugate indulges is trying to make Hill look like a fool, and then kill him.
Recess: School's Out had Prickly getting the Superintendent to stop Phillium Benedict because he was threatening to cancel recess. It worked too well: Although he did certainly stop Benedict from cancelling recess, he also unintentionally got Benedict's job instead, with Benedict being demoted, earning bitter enmity from Benedict.
In one episode where everyone besides TJ and his friends got sick as a result of food poisoning from fish tacos served by the cafeteria cooks, TJ and his friends try to fake sick after being sick (no pun intended) of being the only students at the school, and Gretchen has them use blue tongues and green spots to achieve the perfect way to fake sick to the nurse. It worked. Unfortunately, it worked a bit too well for them, as the sickness that Gretchen chose was actually a biohazard kind of illness that resulted in them being put in quarantine well past when all the other students got better.
Drakken's Bee Bee robots in Kim Possible. He built them to be perfect — which made them realize they shouldn't have to obey him because he wasn't perfect.
Twilight Sparkle's "Want-it-Need-it" spell in My Little Pony: Friendship Is Magic, seen in "Lesson Zero". She uses it to create an Apple of Discord to cause a conflict that she can "solve". It works all too well when all of Ponyville is dragged into the mess.
Another of Twilight's spells goes horribly right in Swarm of the Century. She casts a spell to stop the swarm of parasprites from eating all the food in Ponyville. And it works - the parasprites start eating everything except the food.
Played with earlier in "The Best Night Ever." Princess Celestia invited Twilight Sparkle and her friends to the Grand Galloping Gala to liven it up. They end up being so lively that the party is destroyed. The thing is, Celestia still considers her plan Going Horribly Right an improvement over what the Gala would have been like without their interference.
In "The Cutie Pox", Apple Bloom whips up a magic potion to give herself a Cutie Mark. It works, but then she gets a second cutie mark, and then another, and before long she's got a bunch of cutie marks and finds herself compulsively performing the talents that go with them.
As the Cutie Mark Crusaders find out the hard way in "Hearts and Hooves Day", the "love potion" they made from a recipe in a storybook was more of a "love poison". The prince and princess who took the potion in the story could do nothing but stare into each others' eyes while their kingdom was falling apart. Unfortunately, they only notice this after they've given the stuff to Cheerilee and Big McIntosh, who they barely manage to save from a similar fate.
Yet another of Twilight's spells messes up in "Bats!" Twilight's plan to use Fluttershy's Stare to stun the bats and stop them from eating all the apples works, but it turns Fluttershy into a vampire bat/pony hybrid.
This hits the Young Justice version of Dr T.O. Morrow as well - coming and going. First his attempts to create 'heroic' androids to infiltrate the superhero community and destroy them from within fail due to his creations being too heroic and sacrificing themselves or turning on him outright. Infuriated by this, he decides to create a final perfect android within any such moral inhibitions... who of course immediately turns on him and rips him apart.
In "Dexter's Assistant," Dexter needed an assistant to help him in his newest invention for a science fair. So he took Dee Dee and replaced her brain (which was the size of chewing gum) and replaced it with a new one that made her smarter. Now Dee Dee is much smarter than Dexter was, and knew more about his invention than he did, later when she left Dexter, she won the science fair with her own invention.
In "The Way of the Dee-Dee," Dee Dee spends the entire episode teaching Dexter to loosen up and have fun, which ends with him going on a destructive rampage in his own lab with psychotic glee. She runs out of the lab crying after apologizing to Dexter.
In the Dynomutt Dog Wondercrossover "Dyno-Might", Dexter becomes convinced that Dynomutt is too much of a goofy idiot sidekick to be any help to Blue Falcon, so he decides to design a new "Dynomutt X-90" to replace him. Unfortunately, Dynomutt X-90 believes that All Crimes Are Equal and uses lethal force to deal with even minor crimes such as littering and jaywalking, forcing Dexter to team up with Blue Falcon and the real Dynomutt to take him down.
"I Am Peter, Hear Me Roar" has Peter make sexually inappropriate jokes to a female co-worker and to avoid being fired from his job and getting sued, Peter is forced to learn how to be more sensitive towards women. It takes Peter to being forced to attend a women's retreat camp to understand how women feel. Several weeks later, Peter is no longer insensitive towards women, but his demeanor has changed Peter to become a woman (even to the point where Peter thinks he has breast cancer and is upset that he can't get pregnant). This upsets Lois because Peter is too caught up in his own feelings instead of tending to Lois' feelings. Things return to normal when Lois gets into a fight with another woman, which gets Peter aroused and drags Lois home to have sex, thus returning Peter to his misogynist self.
"The Cleveland-Loretta Quagmire" depicts Cleveland's wife Loretta cheating on him with Quagmire, with Cleveland, in his typical mild-mannered way, simply takes in stride. Peter, hoping to stop him from bottling up his emotions and give him a "revenge lay," attempts to get him to express how he really feels, but when he goes so far as to act out Loretta and Quagmire's affair with an unwilling Brian right in front of him, Cleveland unexpectedly snaps and vows to kill Quagmire, leading Peter to a rare My God, What Have I Done? moment.
"Death is a Bitch" has Peter, worried he has cancer, checked out by the doctor. The doctor confirms Peter is healthy, then gives him a very large bill. Peter writes "deceased" on the bill, to avoid paying. He doesn't have to pay the bill, but Death turns up to collect him, since after all, he is deceased. Oops.
In the Scooby Doo, Where Are You! episode "Go Away Ghost Ship," the gang goes out on a speedboat and use a recorded foghorn to pose as the freighter that Redbeard's ghost is after. Their plan works all too well, and Redbeard's ship rams their speedboat and splits it clean in two.
The final scene in the Looney Tunes animated short "Ready, Set, Zoom!" has Wile E. Coyote donning a female road runner costume to attract his prey. Unfortunately, there's about a hundred starving coyotes waiting behind those rocks.
Another short ends up with the Coyote chasing the Road Runner through a series of smaller and smaller pipes, both ending up shrunken to the size of a bug. They both chase back into the pipe, the Road Runner returning to original height, while the Coyote remains shrunken. At first oblivious to this development, the Coyote jumps and grabs a hold of the Road Runner's leg. Then, after he looks in horror up at the gigantic Road Runner, looks to the audience while holding a sign saying "Well...you always wanted me to catch him.....now what do I do?!?"
American Dad!: In "Escape from Pearl Bailey," Steve's friends, jealous of all the time Steve is spending with his girlfriend Debbie, particularly after he assists her in campaigning for class president against Alpha Bitch Lisa Silver, design a slam page against Debbie while framing Lisa's clique for the deed to ruin her campaign and free up Steve's time. However, they failed to anticipate that Steve would go on a Roaring Rampage of Revenge against those that he believed responsible, disfiguring and otherwise humiliating them.
The Amazing World of Gumball: In the second season episode "The Words," Gumball decides to teach Darwin, who is too polite to actually express his feelings, to be more direct with people and express how he really feels. It works, but as a result, Darwin becomes a complete Jerkass who begins insulting everyone he comes in contact with.
In South Park the creators of Walmart sought to establish the ultimate convenience store chain, and ended up creating an all-consuming monstrosity, that feeds on greed and rampant consumerism, enslaves the minds of its customers and employers and brings misery and degradation to any settlements where it sets roots.
In one episode of King of the Hill, Hank starts working with people in a co-op so he can take advantage of the high-quality steaks they offer. While at first the co-op workers are unsure how to run a store, Hank helps them to make the store better, having the end result of making the hippies far more capitalistic and causing them to sell the store to the Mega-Lo-Mart, which Hank was trying to avoid.
In the Steven Universe episode "Cat Fingers", Steven learns from Amethyst how to use his natural shapeshifting ability and uses it to turns his fingers into miniature cats. In the process of trying to get rid of them, they end up growing all over his body and he has to get help from his muggle dad to cure him.