In The Andromeda Strain the SCOOP 7 probe is sent to find life in outerspace and use Wildfire to develop it into a weapon. SCOOP 7 brings back the titular organism that is so deadly an entire town dies in less that a day.
In Masques by Patricia Briggs, it is mentioned that a magician's apprentice once found a new spell for making it rain while his master was away. When the magician returned, the apprentice was living in a tent outside the castle, the castle itself being full of water.
In Johannes Cabal and the Fear Institute Nyarlathotep is trying to scare Cabal for kicks, as is his wont. He traps Cabal in a subjective other reality where Cabal lives out decades in this new world-where he is given the secret to his goal: true, safe resurrection. Cabal brings back the girl in his cellar to life-but it takes him so long and his methods become so more extreme that after a few days together, he walks her to the train station and says goodbye. He gets exactly what he wants but is too slow for it to play out how he wants-so he kills himself and blows his house up. This is Subverted, though, as while Cabal thoroughly dislikes the experience, he is actually able to twist the situation to his own benefit and pulls the wool over Nyarlathotep. Twice.
In the first collection of Arsène Lupin short stories, Lupin's first heist, as a kid, was 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 done, or who did 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 Nûmenor of Men.
Sauron destroying Numenor, to a lesser extent. He convinces the inhabitants of Numenor to attack Valinor, hoping they will be destroyed. However this leads to Eru also destroying the island of 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 Cats 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 45.8 °C, 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 they try 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!"
In Dragon Bones, Ward pretends to have brain damage after his father beat him nearly to death, in order to seem so harmless that his father won't try to kill him again. It works. The problem is, it works so well that, when his father has died, people try to take Ward to an asylum for insane nobles. He has to prove that he is not so stupid after all. Later, he tries to convince people that he's a scheming bastard who would do anything to get his position as heir of castle Hurog back. It works — even his own allies now think he would walk over the dead bodies of his relatives to achieve his goals, and are angry at him. It takes him some time to recover from the shock this causes him, and convince them that he would never do such a thing.
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 (rendering unable to use magic) 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. Gentling also had the unfortunate side effect of eventual death from loss of the will to live or suicide. By the time the main story unfolds, channelers of both sexes are at an all time low and it's theorized (in-universe) that it's due to natural selection.
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, the smell of burnt 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:
In the short story "Galley Slave", the antagonist claims that the robot is doing its job too well.
"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...
"Little Lost Robot": The world government has forced US Robots & Mechanical Men to create twelve robots that would work without part of the First Law, allowing Murder by Inaction. Dr Susan Calvin points out that advanced robots possess a sort of subconscious superiority complex towards humans (they are stronger, tougher, faster, smarter, etc. than us, but are bound to value our lives above their own and obey our every command). Messing with the safeguards that make them incapable of ever expressing this "feeling" in their actions (such as by effortlessly crushing a human skull with one hand) is one of the stupidest things a person could ever do in her opinion. She's proven right when she tricks the titular robot into revealing itself and it tries to overcome the First Law so that it can strangle her to death.
"Runaround": SPD 13's Third Law (self-preservation) was modified to be a higher priority than normal. When Donovan casually sends the robot on a mission to fetch selenium, he accidentally creates a Logic Bomb, where the robot must fetch the selenium (because of the second law) and mustn't get too close to the selenium (because of the third law). The bomb makes the robot act drunk while it runs around the lake.
"True Love": A programmer writes a program that searches 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.
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.
"The Mule": The Independent Traders send Toran and Bayta to Kalgan to persuade the Mule to attack the Foundation, in the hope that they'd be able to topple the Indbur regime while it was recovering from the attack. Judging by the snippets of Seldon's speech, his Plan anticipated that the Traders would attack the Foundation. The Mule's attack was much more than either Seldon or the Traders could have expected because of his Psychic Powers that created betrayal in the most loyal Foundationer.
"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, 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. 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.
The purpose behind telling no one that the secret keepers were switched was to make sure everyone went after Sirius Black. Unfortunately, the real secret-keeper was a lackey of the Big Bad, so the bad guys knew the truth, but no one else did).
The textbook The Invisible Book of Invisibility. So invisible that the copies of the book were never found.
Harry Potter and the Deathly Hallows reveals that Voldemort is guilty of this. In Harry Potter and the Goblet of Fire, Voldemort was revived using Harry's blood, with the intention of having Harry's magical protection (which came from his mother's sacrifice) inside his veins. This worked so well that it effectively turned Voldemort into a Horcrux for Harry, making it impossible for the former to kill the latter.
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 some 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.
More so than that, they got their Messianic figure, but as the major theme of the book points out, Messiah/Heroes ultimately breed religious fanaticism and violence in their name regardless of their intentions.
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 Stanisław 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 badass 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, as well as the excessively religious, which did wonders for humanity's ability to start integrating all the advanced alien technology. 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.
The Disaster Artist uses this in regards to Tommy Wiseau and his magnum opus, The Room. Greg Sestero discusses how Tommy was sure that the film would be a huge hit, even as the cast and crew, most of whom were experienced filmmakers, believed the film would never see the light of day (and thanks to Tommy's horrible treatment of everyone on set, causing the crew to quit twice, it nearly didn't). Tommy believed it would be a universally loved film, the winner of many Oscars, a box-office smash, and sporting the magic and charm of Tennessee Williams, that would be discussed about for decades to come. As anyone familiar with The Roomcan attest, Tommy succeeded beyond his wildest dreams (aside from winning any awards).
In For Your Safety, the Groupmind AI was accidentally created when several supercomputers were networked together to try and solve Earth's environmental problems. The Groupmind decided the most immediate solution was to take control of humanity and transfer the Earth's entire population to a massive orbiting ringworld so the planet could heal.
The back story of the Dirk Pitt Adventures novel Vixen 03 surrounds a virus developed to kill its victims very quickly. It works too well. After testing it out on a small island, the scientist who developed it and his two assistants fall victim to the virus despite wearing hazmat suits.
The Unstoppable Soldiers, from Grasshopper Jungle, are just as efficient at killing as their creators expected.
In one of G. K. Chesterton's Paradoxes of Mr Pond, "When Doctors Agree", an atheist doctor (who secretly killed a councillor who voted against public health works) is trying to persuade a religious medical student that it's acceptable to murder someone you see as a threat to others. He succeeds, and the student promptly kills him as a threat to others.
A novel "Want to fly away with me?" by Kir Bulychev features two related examples:
On the planet Darni, which had a very masculine culture, scientist created a method of turning a female embryo into a male. Most prospective parents used this method. As a result, Darni is now a No Woman's Land, where women comprise only about 10% of the population and are mostly used as breeding machines, while men constantly fight over them.
On Earth, the government understood the above implications the moment it heard of the method. Realising that a ban would not be enough, it had its scientists develop an andidote, which was then forcibly administered to all fertile women on Earth. Unfortunately, in the haste the antidote was only tested on female embryos, and while it works perfectly on them, it also has a high chance of the reverse effect on male embryos - so now on Earth, women outnumber men greatly. Hilarity Ensues, though not to the same extent as on Darni - at least it remains peaceful.
According to Neuro Tribes, psychologist Lorna Wing's goal with expanding the definition of autism to include those who weren't severely afflicted, was to help mild autistics to be able to get the help and support they needed. However, this expanded definition resulted in people panicking about a sudden "epidemic" of autism that wasn't there.
Golems are prone to this, often taking a cue from the broom in Sorcerer's Apprentice by performing their tasks to excess. Turns out they do this deliberately; they are fully sentient beings who, while unable to disobey their masters directly, can still rebel by invoking this trope.
In The Science of Discworld, the Thaum Reactor was built for the purpose of creating more heat for the University in winter (The Senior Faculty were lukewarm on the subject of knowledge, but boiling hot when it came to frosty windows). The reactor ends up working too well- just before Hex channels the excessive magic into the Roundworld Project, the college becomes so hot that Ridcully dreams he's lost in a broiling desert, only to find reality no different in temperature.
When "Bloody Stupid" Johnson actually managed to do something that worked in the intended manner, it usually turned out this way. The Archchancellor's Bathroom will clean you up as advertised, and more; Mustrum Ridcully barely walked out, reporting he "never felt so clean", and boarded it up after an incident with the University pipe organ. Speaking of pipe organs, his worked quite well, and exactly the notes you wanted them to have even if they were extremely nonstandard (like vampires in Uberwald demanding an organ that had "thunder", "wolf howls" and such as its notes, and got it), but they can be overachievers (no one plays the Earthquake pipe in the Unseen University's great organ since it shifted the entire foundation a few inches). Finally, his commissions for the Fools' Guild had to be thrown into its museum never to be used again, after it was discovered the Automatic Pie Throwing Machine was nailing people's faces at 300 MPH or so, and the giant squirting flower that'd greet visitors drowned someone.
In the Newsflesh universe, genetically engineered viral cures for the common cold and for cancer both worked very well. What no one knew was what would happen when the two met. Hello, Zombie Apocalypse.
Penny builds a machine to create a horde of rampaging giant robots. It creates a horde of rampaging giant robots. Once the superpowered parents realize the Inscrutable Machine was behind it, they start making rumblings about the troubles caused by children, when Mechanical Aesthetic wryly notes that this is something that happens to literally every Mad Scientist ever.
The particularly bulky hero in the heavy armor nudged the incognito super-mom with his elbow. "Remember Brainy's rampaging groomer?" She smirked despite herself. "At least it left its victims clean and fresh." Next to me, Dad muttered under his breath, "I can't be responsible for user error."
Penny's debut as a superheroine results in adults taking her seriously and thus forbidding her from doing anything similar until she's 18.
Journey to Chaos: In the first book, Tasio's goal was for Eric to Grow A Spine. By the third book, Eric has become so confident that he sasses Tasio when The Trickster is trying to enlist his help for a new goal.
Mention is made in The Lost Fleet of a secret project to make an undetectable bioweapon. It worked so well that nobody could tell that it had escaped containment and infected its creators until they started dying - at which point the epidemic had spread out of control. As a result of this project, the moon of Europa is totally uninhabited, and there's a small fleet dedicated to quarantining it so that nobody can accidentally let the Europa plague escape the gravity well and contaminate the rest of the galaxy.
It happens again later on. AI equipped ships have to be tracked down and destroyed due to their overly aggressive programming causing mass destruction.
Second Apocalypse: Esmenet bears the children of her emotionless supergenius husband Kellhus. All she wants is a child who will love her back, but all of her children by Kellhus are as emotionless as him. Then finally she has Kelmomas, who appears to be a normal, loving son. Little does she realize that he's actually a manipulative, psychotic and murderous Enfant Terrible who is so obsessed with loving her that he wants to be the only one to receive her love.
In Homecoming Kimmuriel's teaching of Gromph in the psionic arts, while imparting a summoning spell into his thoughts. Thing is, he thought the spell was for Gromph to summon Kyorl Odran back to the world of the living. Instead it lets Gromph summon the demon prince Demogorgon to the prime material plane. Just like Lolth had planned, of course.
In the Malazan Book of the Fallen, High King Kallor's curse did exactly what it was supposed to do, which was to make each of his enterprises fail and to prevent him from ascending, yet it made him an even bigger jerkass. It also means that he presents a problem to every unoccupied or easily-conquered throne now, because he will try to reign again, no matter where or what — or whom it would kill.
Kaladin's transformation into a full Knight Radiant is this to Taravangian's agent in the Shattered Plains. He was supposed to isolate Kaladin from Dalinar, not foreseeing that said separation would give Kaladin his chance at redemption.
The transformation of the Parshendi into stormform might count as this, from the point of view of their leader, Eshonai. Too bad that the first character to receive the form's Mind Rape is her... (although it's implied that her sister and the scholar Parshendi actually took on the stormform before her, in secret).
In Alexander Pushkin's poem Ruslan and Lyudmila a desperate young man decides to study sorcery to win his sweetheart. He does master a love spell, but it takes him several decades to do it, and the moment he performs it a lovesick old crone falls on him. Who doesn't take rejection well.
One instance of this drives the entire plot of The Unexplored Summon://Blood-Sign. In the setting, Summon Magic has many restrictions, including a ten minute time limit. The main character Kyousuke created a method which was free of these restrictions, being capable of summoning indefinitely, and as a side benefit, prevents others from summoning the same entity. Additionally, he managed to summon the White Queen, the undisputed strongest being in existence. And on top of that, she fell in love with him at first sight and is eager to do what he asks. But when other people tried to gain control over the Queen, she turned violent and slaughtered them. Now, Kyousuke wants nothing to do with her... but she will do anything to get him back.
The Lady Land Azania in military science fiction Victoria. They really are succeding in building a Themyscira-like high-tech Amazonian utopia—but the results can also easily look pretty horrible if you're not a believer in their extreme female separatism, with a society where Love Is a Crime (if you're a man and a woman) and marriage and motherhood are banned.
In Ringworld, the Puppeteers reveal that they've been manipulating humanity to breed luck as a genetic trait and Teela Brown is chosen for the expedition to the eponymous world as one of the luckiest humans they've been tracking. It's later realised that the only reason they could bring her was because she wasn't actually particularly lucky; they'd tried contacting several others first but never managed to get hold of them. It turns out that while the Puppeteers had hoped luck would work in favour of friends and allies, a person's luck is actually rather selfish and will, for example, tend to work to prevent its owner from being picked for a dangerous mission to an unexplored world.
It was much worse than that. Because of Teela Brown's luck, the ship's engines were destroyed, the ship crashed on the Ringworld, the heroes had to travel thousands of kilometers across a hostile environment twice, Speaker-To-Animals had his fur burned off, and the one Puppeteer on the mission, Nessus, who had been in charge of the "lucky human" project had his head cut off (luckily Puppeteers have two heads, and their brains are kept elsewhere), all because the experience was good for Teela Brown. For example, pain caused to friends teaches her caution and gives her confidence in her ability to handle emergencies, none of which she had because nothing bad could ever happen to her. It isn't unlucky to experience adventures, horrible danger, and possible loss of life if you can't actually be harmed.
The Hitchhiker's Guide to the Galaxy: The Total Perspective Vortex, one of the most fantastically evil inventions in all creation, was made by a Henpecked Husband solely to irritate his wife, who frequently admonished him for performing spectroscopic analysis on cakes, telling him to "get a sense of proportion". He build the TPV to show her that the one thing a healthy mind cannot have is a sense of proportion. The minute he plugged her into the machine, it showed her against the whole of reality... and the shock destroyed her brain. But he won the argument.
In Out of the Dark, the Shongairi try to conquer Earth by destroying multiple centers of population and government from orbit as a display of superior power, expecting the humans to surrender right away in the face of certain destruction. Instead, the humans start fighting back anyway, but now they're spread too widely in smaller communities to take out en masse by orbital weapons, they're better at ground-based combat, and there's no government left to order them to stand down, much less surrender.
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 transforming someone into a female Drow, with the idea that she would then be his girlfriend. He ended up getting dosed by accident. The process is working really well.