History Main / DangerousForbiddenTechnique

** Ki Rata, a martial style so dangerous to oneself and others that for centuries it was only practiced by a group of monks for only one reason - so they'd be capable of killing anyone else who tried to use it. It requires absolute concentration and breath control to be maintained at all time, to the point that a lapse in concentration while using Ki Rata will literally tear the body asunder. [[spoiler:Ki Rata also has a forbidden technique called "Slayer of Immortals", which basically works [[CastFromHitPoints by opening all the body's energy channels and turning the user's own body into fuel for their Atum]]. While it provides an ''immense'' power boost while maintained, the technique is implied to be fatal to its user.]] Solomon David is its most prominent user, fitting his status as Demiurge of {{Pride}}; [[ControlFreak he'd accept nothing less than perfect control anyhow]].

*** Averted with its Yurchenko equivalent, the Yurchenko double back (a roundoff entry onto the springboard, followed by two flips in the air before landing). Despite the fact that this vault is considered even ''more'' dangerous (while the "Prod" could very conceivably result in spinal injuries if missing enough rotation, the chance is lower than in the double back, as due to the mechanics of forward vs. backward rotation, an under-rotated front flip is more likely to end up with a gymnast landing flat on her back, which isn't especially likely to cause major injury, but an under-rotated backflip has a good chance of landing on the ''head''), there are no special rules pertaining to it, only the aforementioned safety collar rule that applies to all backward vaults. In fact, when Simone Biles became the first woman to perform the skill in international competition, she ended up being assessed a 0.5 point deduction for the presence of a spotter, despite said spotter being obviously there to provide an extra guard against serious injury with such a risky skill. However, while it's never been banned internationally, Marta Karolyi did effectively ban the skill for USA gymnasts during her tenure as National Team coordinator: the first time she saw [=McKayla=] Maroney (widely considered the greatest vaulter in the history of the sport) attempt the skill at a national team training camp[[note]]almost certainly onto something much more forgiving than a regulation landing mat[[/note]], Karolyi very firmly told her to "Never do that again!!" and then chided Maroney's coach for allowing it because she was so afraid that Maroney could be catastrophically injured. While she might not have outright made this a written rule, this reaction sent a clear message that even training this vault wouldn't be allowed as long as she was in charge of the program (much to Maroney's disappointment, since she wanted to be the first to compete it internationally on the women's side). The moratorium clearly ended with Karolyi's retirement, though, since Biles was allowed to train and perform the skill in the subsequent quad.

*** Its Yurchenko equivalent, the Yurchenko double back (a roundoff entry onto the springboard, followed by two flips in the air before landing), is considered even ''more'' dangerous. While the "Prod" could very conceivably result in spinal injuries if missing enough rotation, the chance is lower than in the double back[[note]]due to the mechanics of forward vs. backward rotation, an under-rotated front flip is more likely to end up with a gymnast landing flat on her back, which isn't especially likely to cause major injury, but an under-rotated backflip has a good chance of landing on the ''head''[[/note]]. While it's never been banned internationally, Marta Karolyi effectively banned the skill for USA gymnasts during her tenure as National Team coordinator: the first time she saw [=McKayla=] Maroney (widely considered the greatest vaulter in the history of the sport) attempt the skill at a national team training camp[[note]]almost certainly onto something much more forgiving than a regulation landing mat[[/note]], Karolyi very firmly told her to "Never do that again!!" and then chided Maroney's coach for allowing it because she was so afraid that Maroney could be catastrophically injured. While she might not have outright made this a written rule, this reaction sent a clear message that even training this vault wouldn't be allowed as long as she was in charge of the program (much to Maroney's disappointment, since she wanted to be the first to compete it internationally on the women's side). Apparently, however, the moratorium ended with Karolyi's retirement, as it was a fellow American gymnast, Simone Biles, one of only two gymnasts in recent history who might match Maroney on vaulting[[note]]the other is Rebeca Andrade of Brazil[[/note]] who, in 2021, became the first female gymnast ever documented to have performed the skill in competition, and two years later she became the first woman to perform it in a international competition, officially codifying the skill in the Code of Points. Despite its danger, however, Biles' experience of performing the skill on the international stage turned out to be an inversion, as she ended up being assessed a 0.5 point deduction for the presence of a spotter, despite said spotter being obviously there to provide an extra guard against serious injury with such a difficult skill.

* Another naval example would be the Japanese mounting the infamous "Long-Lance" torpedo on their cruisers. The torpedoes were stealthier than most, but also much more volatile. Thus, if they were hit while still on the ship the resulting explosion often crippled the ship. This happened to the cruiser ''Chokai'' during the Battle of Samar, which was fired on by the single 5" gun of the escort carrier USS ''White Plains''. While [[JokeWeapon usually incapable of penetrating a cruiser's armor]], one hit set off eight torpedoes, [[MadeOfExplodium each with a 1000-pound warhead and a tank full of pure oxygen propellant.]] The resulting explosion [[CherryTapping knocked out the engines]] and the ''Chokai'' had to be scuttled.

** The ''Series/StarTrekTheNextGeneration'' episode "The First Duty" involves a maneuver called the Kolvoord Starburst, which involves five ships flying at each other, then opening their plasma vents and evading at the last moment. Done correctly, their engines ignite the plasma and the resulting trail forms a star with a burst from the center. Done incorrectly, you get one or more exploded ships. The last time it was attempted a century earlier, all five cadets were killed. [[spoiler:Turns out it was attempted again, and once again it ended in a crash; four of the cadets managed to get out this time, but there was still one fatality.]]

* In ''Fanfic/{{Origins}}'', a ''Franchise/MassEffect''[=/=]''Franchise/StarWars''[[spoiler:[=/=]''[=Borderlands=]''[=/=]''[=Halo=]'']] MassiveMultiplayerCrossover, Dr. Kevin Filner comes up with one. In order to fight [[spoiler:the Flood]] the heroes need ships that don't have crews. Unfortunately, all the power sources that have been used for various warships so far are either inadequate or run on some form of {{Unobtainium}} like hypermatter. Consequently, he suggests using biotic batteries, like a certain [[HeelFaceTurn villain-turned-at-least-nonthreatening]] -- Sarah. He repeatedly lampshades how much trouble he will be in for suggesting such a thing, and considering these are [[MamaBear Jack's]] students we're talking about, he's probably right.

* In ''WesternAnimation/{{WITCH}}'', the [[ElementalPowers Guardians]] can choose to transform into living embodiments of their elements, giving them PhysicalGod levels of power -- at the risk of losing their personalities and humanity, and being left open to mental domination from outside forces, such as BigBad Nerissa. [[spoiler:Fortunately, the one time they do this, they manage to come back- barely]].

*** Its Yurchenko equivalent, the Yurchenko double back (a roundoff entry onto the springboard, followed by two flips in the air before landing), is considered even ''more'' dangerous. While the "Prod" could very conceivably result in spinal injuries if missing enough rotation, the chance is lower than in the double back[[note]]due to the mechanics of forward vs. backward rotation, an under-rotated front flip is more likely to end up with a gymnast landing flat on her back, which isn't especially likely to cause major injury, but an under-rotated backflip has a good chance of landing on the ''head''[[/note]]. While there is as yet no official ban on the skill at the international level (probably in part because it has yet to be attempted in women's competition), Marta Karolyi effectively banned the skill for USA gymnasts during her tenure as National Team coordinator: the first time she saw [=McKayla=] Maroney (widely considered the greatest vaulter in the history of the sport) attempt the skill at a national team training camp[[note]]almost certainly onto something much more forgiving than a regulation landing mat[[/note]], Karolyi very firmly told her to "Never do that again!!" and then chided Maroney's coach for allowing it because she was so afraid that Maroney could be catastrophically injured. While she might not have outright made this a written rule, this reaction sent a clear message that even training this vault wouldn't be allowed as long as she was in charge of the program (much to Maroney's disappointment, since she wanted to be the first to compete it internationally on the women's side). Apparently, however, the moratorium ended with Karolyi's retirement -- Simone Biles, one of only two gymnasts in recent history who might match Maroney on vaulting[[note]]the other is Rebeca Andrade of Brazil[[/note]], not only trained the skill but successfully performed it in a domestic competition in 2021, though she has to date never performed it in international competition (which would officially codify the skill in the Code of Points).

* Right behind the Burning Hammer and Ganso Bomb, sittingly comfortably next to the Kudo Driver, is The Muscle Buster, a move that originated not in the ring but in the ''Manga/{{Kinnikuman}}'' manga comic after the mangka saw Mexican luchador Chamaco Valaguez's La Valagueza submission hold and thought Wouldn't that hurt more if he dropped to the mat and drove the other guy's neck into his shoulder?". Wrestling/AllJapanProWrestling heavyweight Kodo Fuyuki was the first man crazy enough to try it in the ring, but most wrestlers use Wrestling/SamoaJoe's safer variation where he always grabs the opponent from the top rope while standing on the mat, walks to the middle of the ring and falls backwards in a suplex motion that puts the recipient on his back. This more cautious method was used by Joe for over a decade with minimal incidents until it was called "reckless" by Wrestling/BretHart after it damaged Tyson Kidd's neck and sent a shock down his spinal chord, making Tyson fear he was paralyzed. Tyson wasn't but still ended up hanging up taking WWE's offer to become an agent and hanging up the boots.

* The Burning Hammer[[note]]Putting the opponent on your shoulders in an Argentine Backbreaker position and then ''dropping them straight on their head''[[/note]] is considered to be flat-out the most dangerous move in all of Professional Wrestling. The innovator of the move, Wrestling/KentaKobashi, has only used the move seven times in his entire career, and every single time [[GodzillaThreshold it has put away the opponent for good]]. This fact just added to the JustForFun/HolyShitQuotient during the Wrestling/WWECruiserweightClassic where [[spoiler:[[Wrestling/LondonAndKendrick Brian Kendrick]], a veteran who was doing anything he could to stay in the tournament, used the move against Wrestling/KotaIbushi in a last-ditch effort to beat him. And even then, it wasn't enough to put Ibushi away.]]

* The Styles Clash is fairly safe by pro wrestling standards. The "defender" has very little work to do and the "attacker" role is not very complex, which is amazing considering it originated from a botch of the much more dangerous powerbomb, which in almost every other situation require a lot of work on both sides to be safe. Ironically, The Styles Clash ''is'' a really dangerous move if taken improperly. Wrestling/YoshiTatsu botched receiving it and ended up with a broken neck, but Wrestling/AJStyles has grown attentive and actually saved James Ellsworth from injury by noticing he tucked his chin[[note]]tucking your chin forward is the normal way to protect yourself when receiving most moves, but as the Styles Clash is an ''inverted'' mat slam this is the ''opposite'' of what you're meant to do to protect your neck in this case[[/note]] and landing on his hands.

* ''VideoGame/SonicTheHedgehog'':

* German author Hans-Hellmut Kirsch, in one of his "Gunner Asch" novels set in WW2, fictionalises an actual incident where a young anti-aircraft gunner skips several steps in the taught loading and firing drill, simply to get more shells in the air among the attacking American bombers. This works fine and his crew manages to double their firing rate. Until the semi-automatic breach of a heavy flak gun pulls in, and then slams shut on, the gunner's right arm. The rest of the crew then realise this is why the drill was evolved this way - to load the shell, and not somebody's arm well past the elbow.

* Overuse of power in ''Manga/GiantRobo'' can lead to nasty consequences. A mook burns himself to near-ashes with his pyrokinesis trying to keep his buddies warm, Alberto the Shockwave [[spoiler:breaks apart after absorbing the Monster Sphere's energy field]], and several characters' powers run fatal risks.

** There's also drawing power from the same source. The [[MemeticMutation "Too much Pink Energy is dangerous!"]] meme comes from this as there's no idea what may happen if two people use powers from the same source at the same time. In ''Series/PowerRangersMegaforce'', the Ranger Changes the Super Megaforce team goes through is only temporary while in ''Film/MightyMorphinPowerRangersOnceAndAlways'', Rocky and Kat are willing to use the Proxy Power Coins despite the danger to save their friends and stop Robo-Rita.

** Series/PowerRangersBeastMorphers features [[SuperMode Fury Mode]], a battlizer for the Red Ranger. It’s powered by Fury Cells which have the negative affect of increasing the wearer’s [[DrunkOnTheDarkside aggression]]. Interestingly Fury Mode gets retired the episode after it’s introduced, something of a rarity for this show. The reason for why is partly this trope and partly because the Fury Cells don’t last very long and are in short supply.

** The use of [[SoulJar Horcruxes]] is so forbidden that it's hard to find any information on how to make one because it involves fracturing the soul, and doing ''that'' involves murdering people.

** There's also [[spoiler:the time spell Zelina creates in the Season 3 finale. Magic users in Oz discovered the secret to traveling through time but repressed the knowledge because of how dangerous it was (when Emma and Hook inadvertently use it, they nearly pull a [[Film/BackToTheFuture Marty McFly]] and prevent Snow and Charming from meeting; this could have caused Emma, and quite possibly all of Storybrooke, to cease to exist had they not rectified the situation). Like her sister, Zelina's desire for revenge pushed her to take such action.]]

** The spell Zettaflare shows up, the most powerful BlackMagic spell in Creator/SquareEnix history. Previously in ''VideoGame/BravelyDefault'', it had only ever been used by a FinalBoss being fueled by the power of an evil butterfly. [[BewareTheSillyOnes Donald Duck can cast it on a spur of the moment]] at the cost of using nearly all of his life force and knocking himself unconscious for a while. Goofy indicates he's done this before.

*** In the game's lore, White and Black Magic are treated as this. The overuse of both schools of magic during the War of the Magi led to the Sixth Umbral Calamity, seriously draining the planet of its aether in the process. As such, both White and Black Magic are considered forbidden arts under Eorzean law, with very few exceptions ever allowed. The Padjal of the Black Shroud can safely use White Magic, since they are keyed into the elementals, and any who practice White Magic without their blessing is considered an outlaw. Black Magic, meanwhile, is outright banned because those who practice it often cause widespread death in their wake, with the PlayerCharacter being given a pass because they are [[TheHero the Warrior of Light]]. The disastrous results of the abuse of White and Black Magic also gave way to [[RedMage Red Magic]], which is a more {{Downplayed}} take on this trope: instead of drawing aether from the planet, Red Magic [[CastFromLifespan uses the aether in the caster's body]]. Overuse of Red Magic won't endanger the planet, but it can imperil the user's life, hence the Red Mage's use of special crystals to amplify the effects of smaller amounts of aether.

** [[spoiler:Izanagi]] allows users to cast genjutsu on ''themselves'' that can briefly override reality. As a tradeoff, [[spoiler:the eyes used to cast the genjutsu will be permanently blinded.]] The only workaround to this seems to be [[spoiler:possessing the incredible regenerative properties of Hashirama's Senju cells, as Madara was only able to restore the sight of his sacrificed eye by incorporating said cells and awakening the Rinnegan. Also, combining Izanagi and Senju cells extended its duration up to a whole minute per eye]]. Because of this, the Uchiha declared it a Kinjutsu, along with its counterpart, [[spoiler:Izanami, which trapped its target in a StableTimeLoop until tey accepted the outcome they were trying to avoid. Even Edo Tensei-revived shinobi aren't immune to the blinding, as Itachi showed]]

Compare DeadlyUpgrade, DealWithTheDevil, CastfFromHitPoints, CastFromLifespan, CastFromExperiencePoints, ExplosiveOverclocking, SacrificialRevivalSpell, and DeathOrGloryAttack. See also GodzillaThreshold and LethalHarmlessPowers.