-> '''Roy''': It was just a joke! We didn't know Mrs. [=McNulty=] was allergic to weasels!
-->-- ''Webcomic/TheOrderOfTheStick''

Pulling {{Practical Joke}}s on others is all well and good in a comedy -- it's part and parcel of the laugh department, and we love watching some pompous ass get taken down a peg or two in some clever and humorous fashion. But in a drama, mystery or horror movie, a practical joke, if it's not played with cruel and malicious intent by cruel and malicious people, has a very high chance of [[GoneHorriblyWrong going horribly wrong]] and ending with somebody getting seriously hurt or even killed as a result of the prank, such as the old guy you meant to give a harmless scare turning out to have a heart condition, or someone cracking their skull after slipping on a BananaPeel, or any number of other horrible unforeseen consequences.

If you're in a drama, you will most likely have to deal with the fallout, emotional and otherwise, of what you've done, with plenty of {{Anvilicious}} CantGetAwayWithNuthin overtones. And god help you if this happens in a horror movie, as chances are excellent that your victim or one of their loved ones will come after your sorry hide for some [[RoaringRampageOfRevenge very bloody vengeance]], even if they have to [[BackFromTheDead rise up from the grave]] to do it.

Some deadly pranks are ''meant'' to end in the other person getting hurt or killed, like the variety of the PrankDate that ends in the victim getting robbed, raped or killed, and such pranks signify that their perpetrators are utter scum who get their amusement from making other people suffer.

Contrast MassiveMultiplayerScam. Also contrast YouthIsWastedOnTheDumb.

----
!!Examples:

[[foldercontrol]]

[[folder:Anime and Manga]]
* In ''Manga/RosarioToVampire'', Mizore [[spoiler:pranks Kurumu into thinking Gin took her virginity]]. It becomes this trope when it's revealed that [[spoiler:hurting a succubus's heart too much can be fatal]].
* More than one case in ''Manga/DetectiveConan'' can have its roots and motivations traced to one of these, with someone related to the people fatally pranked seeking punishment for those who came up with the whole bad joke. The most notorious is the [[spoiler: ''Naniwa Murder Case'']]: [[spoiler: Five Osakanites get their very strict driving instructor drunk after graduating from their driving school. Instructor crashes his car and gets killed. Death is filed under accident and the five Osakanites get scott free. 20 years pass. Son of the dead instructor is a cop and chases a SerialKiller, who turns out to be one of the Osakanites. SerialKiller has a VillainousBreakdown as he finds out who is pursuing him and spills out the truth. Son of the dead instructor starts chasing and killing the other Osakanites left as revenge for their Deadly Prank. [[TearJerker/DetectiveConan It ends up in massive tears]].]]
* In episode 6 of ''Manga/{{Nobunagun}}'', some researchers at a remote lab in Alaska haze a new recruit by telling him he's eating meat from a dead alien. He goes nuts and kills them all. Even worse, he thinks eating the meat caused him to become an alien himself and he tries to side with them against humanity, calling them his real family. An alien kills him right after he frees it from containment.
[[/folder]]

[[folder:Comicbooks]]
* Bobby in ''[[HackSlash Hack/Slash]]'' gets one of these when a couple of guys put him in a chamber and pretend to gas him. When they try and shut the gas of it fails. He later turns into one of the slashers.
* This is how TheJoker sees many of his murders: Simply as pranks.
* One standalone issue of ''ElfQuest'' features a couple of human boys who decide to play a prank on the "spirits" (elves). It all goes disastrously wrong, with two elves dying and one of the boys being executed by the human tribe's elders.
* In "Last Laugh!" in ''Tales from the Crypt'' #38, the main character dressed several pounds of bloody horse meat in boys' clothing, dumped it on the railroad tracks and then screamed right after a train went by as a "prank" on several local boys playing nearby. This resulted in a chain reaction which got the town doctor's wife and two sons killed. Naturally, this being {{EC Comics}}, said doctor played a rather improbable revenge "prank."
[[/folder]]

[[folder:Film]]
* The '80s slasher film ''Film/TerrorTrain'', starring JamieLeeCurtis (of course) and David Copperfield (what?), has this as the killer's motivation. A group of sadistic med-school frat boys lead a socially-awkward student where he is told a girl is waiting to have sex with him. Of course, once he pulls off the bed sheet, the [[PrankDate "girl" turns out to a dismembered corpse]]. Naturally, he freaks out and ends up in a mental asylum. Of course, this almost gets them kicked out of school, but surprise-surprise, three years later during a graduation train ride, the frat boys (as well as a wrong place, wrong time David Copperfield) start getting knocked off...
* This is the origin of Troma's ''Film/TheToxicAvenger''. Geek Melvin is set on a PrankDate with the TheDitz / TheVamp. After some events that involve a ballet tutu and a sheep, he's laughed out of the gym locker room by what seems like the entire town, and takes a running jump out of the window and into a vat of radioactive waste. Yeah...
* ''Film/UrbanLegend's'' villain was set off by [[spoiler:the death of her boyfriend, who was killed in a car accident, the result of the other characters scaring him by putting their flashers on and chasing him, in imitation of an urban legend.]]
* The high school film ''Film/{{Jawbreaker}}'' features the main characters staging a kidnapping for their friend's birthday. Unfortunately, this goes horribly wrong when the intended victim chokes on the jawbreaker they were using to gag her.
* In ''Film/TheOrphanage'', [[spoiler: Tomas died as a result of this combined with his own refusal to be seen without his mask. However, the standard horror-movie revenge thing is enormously subverted, as yes, his mother did kill all the kids responsible, but no, the disappearance of the protagonist's kid has almost nothing to do with the entire business.]]
* A similar prank-deranges-and-deforms-victim premise drives the film ''Film/SlaughterHigh''.
* Provides the motivation for the killer in the early 80s slasher film ''Film/TheBurning''. It tells the story of a [[CrustyCaretaker cruel, alcoholic caretaker]] at a summer camp (nicknamed Cropsy, after the huge garden shears he carries) who falls victim to a prank that went out of control and leaves him horribly burned and disfigured. Following his release from hospital, he returns to his old stomping ground and begins a murder spree. Naturally.
* In ''Film/TheButterflyEffect'', Evan and his friend put a stick of dynamite in someone's mailbox to blow it up. A woman carrying a baby happens to come to check for mail at the worst possible moment, and they're both killed when it detonates.
* In the movie ''Film/TheHouseOnSororityRow'' sorority girls play a prank on their house mother, but it goes wrong and she [[spoiler: ends up shot and killed. They hide her body in the pool.]] Later someone [[spoiler: starts killing them.]] [[spoiler: It turns out to be her mentally disabled son she [[MadwomanInTheAttic kept in the attic]] who saw his mother get shot and wanted revenge.]]
* ''Film/SororityRow'' released in October 2009 is a remake of ''The House on Sorority Row'' but with a slightly different plot. The Sorority sisters have one of the sisters pretend to die in order to prank a boy. At an [[spoiler: abandoned coal mine shaft they pretend they have to look for something to dismember the body. The boy thrusts an object through her body, killing her (he thought she was already dead). They hide the body in the coal mine shaft, but later they get messages on their cell phones from someone saying they know and threaten to report them to the police and then someone starts killing them]].
* ''Film/PennAndTellerGetKilled'' features Creator/PennAndTeller one-upping each other with pranks, to the point that when a murderous stalker fan starts trying to kill Penn, he believes that it's just another of Teller's tricks. It turns out that [[spoiler:the fan is Penn's prank on Teller, but Teller gets so freaked out that he purchases a gun unbeknownst to Penn and accidentally shoots him just when he's revealing the prank. Teller and everyone else related to the prank kill themselves in grief, and then random people who stumble upon the scene begin shooting themselves in horror as the credits roll]].
* ''Film/TheCatacombs'' features a young woman visiting her sister in Paris. The sister invites her to a secret underground rave in the Parisian Catacombs, where the sister's friends get the protagonist drunk on absinthe. Then, the sister is apparently murdered by a psychopath, and the police raid the rave, causing everyone to disperse before the protagonist can get help. The psycho continues to stalk the protagonist, who suffers some injuries, but eventually manages to dispatch the killer with a pickax. She then runs into her sister and the friends. It was all a joke... they just pumped her full of alcohol and put her through Hell for a lark. Then they realize the protagonist (in a failing mental state) killed the "psycho". They start yelling at her... and she's still holding the pickax...
* ''Film/MeanCreek's'' entire plot focuses around this trope. A shy boy named Sam is getting bullied by a bigger kid at school named George. In retaliation, Sam, his older brother and his two friends and Sam's girlfriend invite George on a canoe ride up a creek, where they intend to steal his pants, push him into the water and make him walk home. They are surprised that the bully actually tries to fit in and be friendly to them, revealing he doesn't have many friends. George's crude behavior though, and his vulgar and violent reaction when he finds out what they intended to do to him, leads to a confrontation where George is knocked into the stream, hits his head on a rock and drowns.
* In ''Film/{{Zombieland}}'', [[spoiler:Bill Murray]] in Zombie makeup decides to play a prank on Columbus and Little Rock by dressing up as a zombie and trying to scare them. This leads to a very surprised Columbus delivering a blast of buckshot through his chest. Not the smartest prank to pull in a world infested by zombies, but the character involved was high on pot at the time.
** There's also kind of a potentially Deadly Scam, if you will, when Columbus and Tallahassee are told that Little Rock is infected and that they have to shoot her. Not the best scam to pull on complete strangers who have obviously seen a lot of action and are probably willing to pull the trigger.
* ''Film/TrickRTreat'' plays with this. A group of kids play a prank on the "idiot savant" kid, [[spoiler: when they dress as zombies and scare her. She, terrified, falls into a ravine and cracks her head on a big rock. After one of the pranksters, horrified, asks "Is she dead?" she turns out not to be; just badly hurt and still panicking. Then the actual zombies show up and eat the pranksters, the savant pointedly doing nothing to save them.]]
* ''Film/TheGraveyard'' uses this trope. Lesson being? Don't play pranks in graveyards.
* A Deadly Prank is ultimately the cause of [[spoiler: Katie Marcum]]'s murder in ''Film/MysticRiver''.
* [[InvertedTrope Inverted]] in ''Film/DoctorX'', in which an ExplosiveCigar saves the protagonist's life by scaring off his would-be attacker.
* The main drive behind ''Film/WhenGoodGhoulsGoBad''.
* Not quite deadly, but the prank in the prologue of ''[[Film/BlackSheepTheMovie Black Sheep]]'' combined the the subsequent news of his father's death causes Henry to develop extreme ovinophobia.
* ''Film/{{Heathers}}''. J.D. and Veronica try to prank Heather Chandler by breaking into her house and concocting a drink made up of orange juice and milk and convincing her to drink it. J.D. pours a glass of drain cleaner as well, and Veronica accidentally switches it. J.D. notices, but decides not to tell her, and Heather Chandler promptly dies when she ingests it. Veronica and J.D. are shocked, and make it look like a suicide. Subverted in the sense that J.D. later reveals that he completely intended this outcome, and tries to kill more teenagers by claiming to Veronica that they're "pranks".
[[/folder]]

[[folder:Literature]]
* In Creator/StephenKing's ''Literature/{{Carrie}}'', not only did the malicious prank at the prom trigger the title character's deadly telekinetic rampage, it also resulted in the death of Carrie's date Tommy Ross as the bucket of pig's blood hit him upside his head and killed him.
* In Creator/StephenKing's ''Literature/NeedfulThings'', the main villain is a store owner, who sells everybody what they wish the most for very low prices, but the customers also have to do a prank on someone. Little do they know that those pranks worsen existing grudges between people, and eventually lead to murderous encounters.
* This makes up the whole of the plot of the novel ''Literature/KillingMrGriffin'' and its [[TheMovie derivative movie]]. Mr. Griffin has a heart condition and dies without his medication.
* Used in ''Literature/HarryPotter'' when a sixteen-year-old Sirius Black tricks Snape into going down a tunnel with Lupin in werewolf form at the end. (Snape survives due to the intervention of James Potter). Disturbingly, both Sirius and Lupin refer to it as a practical joke more than thirteen years after the event, and Sirius doesn't seem to receive any punishment for it.
** YMMV on whether Lupin is justifying it. (Sirius definitely is.)
* In ''Literature/LabyrinthsOfEcho'' by Max Frei, the protagonist was informed that now he's able to spit instant-kill magical poison, he ''will'' do it if very enraged or afraid, and as such got a status of more or less a human GrimReaper. He contemplated spitting at one dirty-mouthed guy while in normal mood, but realized such a joke might cause heart failure. So later he spat at an approaching [[AcceptableTarget insane cannibal]], who in his opinion looked inadequate as a threat, just to scare. [[spoiler:And learned that "really afraid" part was optional after all.]]
* In Rex Stout's ''The League of Frightened Men'' (1935), the second Literature/NeroWolfe book, the titular league permanently disabled an unpopular fellow college student many years ago in a hazing incident. (They're frightened now because after years of patronizing him, they're panicking at the idea that some sudden deaths among them may be due to his having murdered them, and they can't prove it.)
* In ''Literature/GoodOmens'', when the demon Crowley is being hunted by other demons, he precariously balances a bucket full of water over his office door. A bucket full of ''holy'' water. It works.
* In ''Literature/{{Private}}'', after Thomas humiliates Reed in front of the entire Easton Academy campus, Noelle and the rest of the Billings Girls group decide to punish him by kidnapping him as part of a prank. They get him drunk, strip him, shave his head, drive him to a remote area and tie him to the trunk of a tree and leave him there. They intend to drive back after a couple of hours and free him [[spoiler: but things do not go to plan when Thomas is then found murdered.]] This leads to a five book story arc with Reed trying to discover the identity of the killer and clear her current boyfriend's name.
* In the Literature/HeraldsOfValdemar titles, Herald-trainee Talia is nearly killed when some young nobles throw her into an icy river "as a joke" -- too bad they added a PreMortemOneLiner to Talia before they threw her in. (It had been foreshadowed that these students might make an attempt on her life on the off-chance one of them would be named heir to the throne.)
* ''The Ninth Circle'' of the ''Literature/TourOfTheMerrimack'' series begins with a youth dying in a hazing ritual gone wrong.
* Penny swaps Hessa's medication in ''Literature/{{Edenborn}}'' with laxatives. Turns out one missed dose is all [[ThePlague Black Ep]] needs to kill her in quick order. [[spoiler:Worse, Hessa's father increases the meds of his other children to address the mysterious outbreak, upsetting the delicate balance between the disease and the treatment and sending them into death spirals.]]
* ''Literature/PrettyLittleLiars'' [[IncrediblyLamePun sees]] our eponymous foursome planning to hit someone else with a stink bomb; Jenna gets blinded in the process.
[[/folder]]

[[folder:Live-Action TV]]
* ''{{Psych}}'' has this as the murder in Scary Sherry: Bianca's Toast. The sorority sisters intended to scare off a pledge. However, the casement window she was startled into was unlocked and she fell to her death.
* ''Series/{{Supernatural}}'' has two kids inadvertently summon a real monster while playing a prank in "Hell House." In a later season, childish pranks turn deadly in a small town, with a joy buzzer somehow electrocuting its victim, and a teenage girl scratching a hole through her skull after someone put itching powder on her comb. As it turns out, [[TheAntichrist a little boy]] in town is developing RealityWarper powers without realizing it, and the joke items are becoming dangerous because he ''[[ClapYourHandsIfYouBelieve believes]]'' they're dangerous.
** Then there's the trickster, who does this ''on purpose'' (well, more like not caring if he permanently scars or kills someone and will keep doing it). Made worse by the fact that [[spoiler:he's actually an angel under "witness protection" and technically, ThePowersThatBe allow him and even encourage him into killing people to prove he's "Loki".]]
* ''SaturdayNightLive'' uses this trope in its "Pranksters" sketch. The eponymous show presents hidden-camera pranks that start off as harmless. Then Christopher Walken's character shows the video of his prank, summed up best with the quote "I [[UnusualEuphemism pranked]] him to death with a tire-iron!" HilarityEnsues.
* A parody of this is played up in ''Series/ScareTactics'', where the scare victims are tricked into going onto a fake reality TV show called "Fear Antics", where they're put under the impression that they're going to pull a huge fright-based prank on someone for the cameras. However, the other participants ''always'' rig the stunt so that it looks like it goes horribly wrong, causing the victim to think they've inadvertently seriously injured/killed/got in some other deep trouble the person they were supposed to scare.
** Backfires in one episode, when the prank-victim, confronted by the prankster "killer," grabbed a knife and nearly tore into the prankster.
---> "OH FUCK, NO NO NO, YOU'RE ON SCARE TACTICS, IT'S A TV SHOW, IT'S A JOKE, YOUR FRIEND SET YOU UP JESUS CHRIST FUCK."
** In one episode, the prank-victim was fooled into thinking he was trapped in a GasChamber, and he ''broke a hole in the wall''.
* B.J. and Winchester set Sgt. Zale up for one of these in a later episode of ''Series/{{Mash}}'' after Zale plays a prank on B.J. involving a fake grenade.
* The ''Series/MastersOfHorror'' episode "We All Scream for Ice Cream" starts with a childhood prank gone deadly wrong.
* In the ''Series/TalesFromTheCrypt'' episode "Abra Cadaver" a doctor pulls a prank on his brother, scaring him into a stroke and ruining his medical career. The brother never forgets and [[spoiler: gets revenge with another prank years later... killing his brother ''twice''.]]
** Happens in another episode, "This'll Kill Ya", when an asshole doctor thinks he's been poisoned by one of his colleagues. It turns out that his colleague had tricked him to teach him a lesson, but this isn't revealed until after the doctor kills him as "revenge".
* ''Series/DegrassiTheNextGeneration'': "Time Stands Still Part 1" in which Rick is painted and feathered after winning at a game show contest. He goes home and starts looking at a gun in a box...
* The ''AlfredHitchcockPresents'' episode "Beta Delta Gamma" has a group of frat brothers heavily sedate one of their passed-out-drunk brothers and make the other passed-out-drunk brother think he killed him in an alcoholic blackout. Too bad he decided to bury the "dead guy" on the beach and the high tide washed away footprints and other traces...
* In one episode of ''{{CSI}}'', a woman sneaks a large block of dry ice into a guy's room, so that the [=CO2=] fumes would make him sick. He and a woman that he sleeps with in the room die. She protests that she carefully calculated the amount of [=CO2=] be non-lethal. She didn't anticipate that they'd be sleeping on the floor. Since the fumes are heavier than air, the concentration near the floor was high enough to be lethal.
** And in another, a juror dies in the jury room. Turns out that he was honking off the rest of the jurors with his attitude, and had happened to mention his peanut allergy (loudly and repeatedly). One of the others then decided to lace his chili with peanut butter to bring him down a peg or two, not appreciating the potential consequences of his allergic reaction. [[spoiler: She tried to back out of it at the last second, Mind you, a bee - one of his ''other'' allergies - beat her to it.]]
** In the episode "Pledging Mr Johnson", a pledge is murdered under the cover of a fraternity hazing gone wrong.
** A different episode featured a crusty old poker star who drops dead at the poker table. A number of factors contributed to his death, one of which is that the waitress for the table - annoyed at his extended refusal to tip - put eyedrops into his drink, hoping to give him diarrhea. [[spoiler: The eye drops reacted with the large amount of lead he'd had in his system after years of eating pounds of chocolate a day made with cocoa grown in lead heavy soil.]]
*** Anything more than a few drops of many eyedrops formulas, including Visine, will cause death by shutting down the nervous system. Nothing more is necessary. See the Visine example below in the Real Life section.
** Likewise, there's the time a guy who's still alive, just fully paralyzed, ends up on Doc Robbins' table. He was a used car salesman whose colleagues kept playing pranks on one another to unnerve them/take them away from the sales floor. One of them put snake venom in his coffee, which normally would've just given a really upset stomach... if not for the bleeding ulcer.
* In an episode of ''ICarly'', Carly, Freddie and Sam decide to prank Loubert by giving him an exploding muffin basket. They didn't realize it would explode quite so much, dealing serious damage to Loubert, who spends the rest of the episode being tended to by Freddie's mom, which shifts the focus onto a potential romance between the two. By the end, the prank is forgotten and none of the kids receive retribution.
* On ''{{Cheers}}'' the most elaborate prank between Gary and Sam [[spoiler: involved Gary getting most of the city of Boston including everyone at Cheers to convince Sam that Gary had been]] killed by a hologram machine.
* PlayedForLaughs in the second season ''GreenWing''. Joanna gets sick of Statham being happy so, under the advice of Sue, decides to knock him down to his partly miserable old self by scaring him. Since Statham is frightfully scared of gobins, Joanna asks her dwarf cousin to hide under his desk, his face covered in green make-up. and shout "boo!" when he comes in. Unfortunately when he does this, Statham beats him to death with a stuffed heron.
* On ''Series/HowIMetYourMother'' Barney spends a month perfecting an exploding meatball sandwich. It took so long because it had the nasty side effect of decapitating the test dummies.
* There was a Candid Camera-esque show of two guys about to prank a barber. The first guy put a bag of fake blood under his wig, planning to make the barber think he cut too deep. When the fake blood was released and the first guy acted in much pain, the barber apparently went into such shock that it triggered his heart condition. To make matters worse, his friend ran away, and the barber's daughter called the police immediately to the scene. [[spoiler: However, it's all revealed that the REAL prank is on the first guy, by the second guy, the barber, his daughter and the policeman.]]
* An unusual example where the prank is deadly for the prankster in ''Series/{{Defiance}}'' - a young man is persuaded to fire a paintball gun at the incumbent mayor during a mayoral debate, not knowing that an anonymous tip has been made of a plan to assassinate the mayor.
* ''Two Twisted'' episode Finding Frank has a security guard's colleague disappear and calls out desperatly over the walkie-talkies. When the guard goes to find him it turns out to be a [[ScarySurpriseParty surprise retirement party]] but goes terribly wrong when the nervous guard over reacts firing his gun when the lights come on, killing his wife [[spoiler: but as the guard is being led away he drops a a bit of paper that his colleague picks up. It's an invitation to the party with the exact time, location, everything showing that the guard [[SubvertedTrope knew all along and used the party to kill his wife]] framing it as accident. It's even better when you know the actor who plays the guard played a set-upon ExtremeDoormat in his most famous roll.]]
* Averted on ''Series/DocMartin'', but as Martin pointed out, it ''did'' keep him from attending to patients that actually needed his help.
* In ''TheBigBangTheory'', in revenge for an earlier prank, Sheldon shakes Howard's hand with an electrical buzzer, causing Howard to collapse due to a heart condition.[[spoiler: Howard was faking, and [[ZigZaggingTrope uses the opportunity]] to scare Sheldon a second time.]]
[[/folder]]

[[folder:Videogames]]
* The Umgah of ''StarControl'' are like this. Their idea of "pranks" include [[GodGuise pretending to be another race's gods]] and ordering them to attack their neighbors, "accidentally" mixing up the Spathi's reply to the Ur-Quan (leading to a great deal of suffering for the Spathi), dropping an asteroid in another race's ocean, etc. It's heavily suggested that the Umgah are simply insane and don't realize the enormity of what they're doing.
* This happens in VisualNovel/PhoenixWrightAceAttorney: [[ColonCancer Justice for All]] [[spoiler:in case 3, when Regina puts pepper on Bat's scarf. This causes a lion to sneeze while Bat's head is in its mouth, which puts him in a coma. As a result, his brother Acro tries to kill Regina as revenge]].
[[/folder]]

[[folder:Short Films]]
* The short film [[http://www.youtube.com/watch?v=Jmbv8kevQ-E Spider]].
[[/folder]]

[[folder:Webcomics]]
* The incident in ''Webcomic/TheOrderOfTheStick'' with the weasel that provides the page quote.
* A flashback from ''SomethingPositive'' where Davan's father (when he was a boy) played a joke on a complete jerkass bully in hospital. Turns out the boy had a weak heart, and died from shock.
* In a standalone comic by [[Webcomic/CityOfReality Ian Samson]], a novice witch turns her more experienced sister into a dress and wears her for a day, not realizing that the spell she used has no way to preserve her mind, which fades until ultimately dying in the wash, leaving her crying over an ordinary dress.
[[/folder]]

[[folder:Web Originals]]
* [[http://www.youtube.com/watch?v=gWqI0U3pBdA Roommate Alien Prank Goes Bad]]: Two guys repeatedly scare their roommate Chad with alien sunglasses and hands because Chad hates aliens. [[spoiler: Then a ''real'' alien shows up.]]
* ''EverymanHYBRID'' was started as a parody of ''WebVideo/MarbleHornets'', disguised by having the health/exercise regimen appear to be what is being hijacked by Slender Man; in reality, the in-universe characters are using a prop Slendy placed in rather obvious places. Then the ''real'' [[TheSlenderManMythos Slender Man]] finds out about it, and it seems he is not happy in the slightest. [[spoiler: After recent events, the characters are starting to wonder if he would have showed up at some point anyway.]]
** As a matter of fact, this is one of the most common theories: Slender Man came into being... because we made stories about him. He is a living DeadlyPrank. And the worst part? [[spoiler:[[NiceJobBreakingItHero They]] [[TheFourthWallWillNotProtectYou might]] [[FunnyAneurysm be]] [[OhCrap more]] [[RealAfterAll correct]] [[ClapYourHandsIfYouBelieve then]] [[ParanoiaFuel they]] [[HarsherInHindsight thought.]]]]
* In the WebOriginal/FurryBasketballAssociation, a prank on a player who is addicted to cocaine results in him snorting caffeine instead; the pranksters had no idea it would result in the addict screaming in pain. This trope is ultimately inverted as the player is sent to the hospital, where he's convinced to enter rehab.
[[/folder]]

[[folder:Western Animation]]
* A version of sorts happens in ''{{Chowder}}''. After already playing a prank that ruins Mung's catering business, Ms. Endive plays another prank on him, dropping a huge pie on top of him, which turns out to crush him flat. She becomes desperate to keep the accident a secret and eventually decides to leave the country. [[spoiler: Turns out that it was all just a prank by Mung to get back at her for all the pranks she did to him]].
* In the HalloweenEpisode of ''FostersHomeForImaginaryFriends'', Bloo pulls the old snake-in-a-can gag on Mr. Herriman. Herriman has a heart attack and dies, and Bloo hastily buries him in the yard. Herriman then comes back from the dead and unleashes a ZombieApocalypse. No, really! [[spoiler:Well, not really. In the end, it all turns out to be a prank pulled on Bloo by the whole house, only ''it'' backfires when Bloo unleashes a berserk Mac (hopped up on candy) upon them.]]
* Not quite deadly, but ''HeyArnold'' has an episode where Arnold accidentally seriously blinds Helga when he takes revenge on her for some pranks she pulled. She gets better, but the rest of the episode is a bizarre CycleOfRevenge. Leads to a funny conversation(taken from memory, so probably not exact):
--->Arnold: I didn't think it would blind her!
--->Grampa: Well, what did ''you'' think I meant by "it'll release a '''blinding''' light"?
* An episode of ''{{Pucca}}'' has the Vagabond Ninjas prank Sooga Village by releasing termites that eat all the chopsticks, and it all goes downhill from there.
* On ''TheSimpsons'' Bart pranked Homer on April Fools Day with an extremely shaken can of beer. It sent him to the hospital in a coma, but, more importantly, because of it, we had to suffer through a ClipShow.
* ''WesternAnimation/SouthPark'': as a joke two Sea Park employees make the boys think that the killer whale is really [[FreeWilly Willzyx]] and needs to return to its [[SpaceWhale family in space]]. It's all fun and games - ending with a big shootout, one of the employees dead ("I still say it was funny!") and the whale dying on the moon, having been shot there by the Mexican Space Agency.
* On ''WesternAnimation/RegularShow'', Muscle Man plans to prank Mordecai by taping his bed to the ceiling. Then the bed falls on Pops, seriously injuring him. Muscle Man then swears off pranking, [[spoiler:which unfortunatelly leaves the park vulnerable during an epic prank war with another park; the prank war being just as bad as the Muscle Man's prank.]]
* ''{{Sym-Bionic Titan}}'': In "The Ballad of Scary Mary," a high school student named Mary is never seen again after a group of classmates lure her into the woods to tar and feather her. [[spoiler: The trope is subverted at the end of the episode, when it's revealed that Mary wasn't killed, but instead hit it off with a cute biker boy she met in the woods and ran off with him]].
* Squidward did this in ''SpongeBobSquarePants'' because he wanted quiet from all the pranking due to April Fools Day. However, the prank was so cruel and harmful that it caused Spongebob to cry and the citizens to call him out on this. And Squidward looks around to see the damage and [[JerkassRealization realizes that he went too far]].[[spoiler: But it winds up subverted: SpongeBob had planned a GambitRoulette that specifically required he get that injured, and when Squidward finally apologized, it turned out everyone in the town was in on it.]]
[[/folder]]

[[folder:Real Life]]
* Combine this trope with TeensAreMonsters and BuryYourGays, and you have the story of [[http://abcnews.go.com/US/victim-secret-dorm-sex-tape-commits-suicide/story?id=11758716 Tyler Clementi.]]
* [[http://www.newser.com/story/87719/man-dies-after-friends-insert-eel-in-his-rectum.html This story]] about a man who got drunk and passed out, and his friends stuck a 20-inch eel in his anus. Apparently, it was hungry.
* During the TroubledProduction of ''{{Titanic}}'', disgruntled crew members put PCP on the crew's soup. The [[BadBoss main]] [[PrimaDonnaDirector target]], Creator/JamesCameron, vomited upon ingestion, while over 50 people were hospitalized.
* Two Australian [=DJs=] made a prank call to the hospital Kate Middleton, Duchess of Camdridge, was staying in with morning sickness. The receptionist who answered the call fell for the prank and divulged confidential information. Two days later the receptionist was found dead in her home after commiting suicide.
* There have been numerous cases of people putting Visine in drinks, thinking that it's a harmless diuretic. [[http://www.snopes.com/medical/myths/visine.asp It's actually a poison that can kill and induce comas]].
* 13 members of the Florida A&M University Marching Band are facing various criminal charges up to and including manslaughter in the death of their drum major, Robert Champion, after a prank on a school bus went horribly wrong. (In Florida, the hazing itself is a third-degree felony, whether Champion had died or not.)
* Most likely apocryphal, but the pagan harvest festival that would be commercialized into Halloween was SeriousBusiness. Failure to provide hospitality when you had the means to do so could result in legally fatal pranks.
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