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Dangerous Forbidden Technique

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"By opening all eight gates, you could attain power beyond even the Hokage. The only drawback is... you die."
Kakashi Hatake (on the Hidden Lotus technique), Naruto

Power at a Price embodied in a single move or technique, a Dangerous Forbidden Technique is an attack that carries a significant risk of harm to it. Maybe it takes a toll on the user's body or his mind. Maybe it summons monsters or otherworldly forces that are hard to control. Maybe it's just immoral, or it unlocks a Superpowered Evil Side. Whatever the case, there is a very good reason to not use it unless absolutely necessary — usually when the Godzilla Threshold is reached.


Usually, only characters that are already quite powerful are capable of using the move. If another character tried, they would just burst into flames and die. You won't see your average Mook using this. Mooks that can use this are often Elite Mooks, Instakill Mooks, and/or Demonic Spiders.

A common way to use this trope is for an Old Master to teach the technique but insist that the hero isn't ready to use it yet. Rule of Drama dictates that the hero must keep the technique in his back pocket until such time as he has no choice but to use it. It's like a Forbidden Chekhov's Gun, except it has a Necessary Drawback. Attempting to use it may result in either a Heroic or Villainous RRoD.

Japanese works, especially Shōnen, love this trope, as it's a perfect manifestation of one of the core tenets of Japanese culture.


Compare Deadly Upgrade, Cast From Hit Points, Cast from Lifespan, Cast from Experience Points, Explosive Overclocking, Sacrificial Revival Spell, and Death-or-Glory Attack. See also Godzilla Threshold and Lethal Harmless Powers. If a character uses (and survives) the move on a regular basis, it's I Thought It Was Forbidden.


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    Anime & Manga 
  • Naruto is rife with these.
    • A subset of the Shinobi arts are called the Kinjutsu — literally "forbidden techniques". For one reason or another, they cannot be taught or used by the commanding shinobi. Some fatally harm the user, like the Shadow Clone Jutsu, which creates perfect Doppelgangers who take an equal portion of their user's chakra, which is eventually fatal if too many are created at once and/or the sheer backlash the user suffers if too many are killed at once; a version of this is Naruto's Signature Move, although Naruto has a superhuman chakra reserve and a Tailed Beast that can handle it. Others are considered unethical, like the Edo Tensei, which resurrects the dead at the cost of another Human Sacrifice. Edo Tensei is particularly powerful (effectively giving you a Nigh-Invulnerable army of The Undead), which increases the temptation to use it, only for the user to find that at its most powerful, its creations might escape from the user's control. Just using a kinjutsu is not a crime however (only the effect may be), and a few are taught in the course of the plot. So they are not so much "forbidden" but rather "regulated". For example, the Shadow Clone Jutsu can normally only be safely used by Jonin-level shinobi.
    • Initially, Sasuke's Chidori is only supposed to be used twice at a time. The third time he used it, he would have died if he didn't have a cursed seal which nearly took him over. Since then, he increased his own chakra capacity to the point that he can spam it without any ill effects.
    • Kakashi had two forbidden techniques: Raikiri, an enhanced Chidori that requires a Sharingan to be used effectively; and Kamui, which sucks anything he looks at into another dimension. Both are limited by chakra capacity, and the second one deteriorates the eyesight of said eye. He figured out how to increase his chakra capacity (and taught Sasuke how as well).
    • Naruto gets his Wind Style: Rasenshuriken, in the second half of the manga. It's so powerful that it causes widespread cellular damage to the arm he executes it with, including the chakra pathways. The damage is microscopic, so healing jutsu can't repair it, and Naruto's own Healing Factor is so overworked that it reduces his lifespan. Tsunade tells him not to use it again. Then he masters his Sage Mode and perfects it to the point that he can throw it and nullify the risk to himself.
    • Kurama is essentially a Super-Powered Evil Side; at deeper levels, he also shortens his lifespan. Naruto winds up befriending him, which allows him access to his full power without having to physically transform.
    • Tsunade's regeneration jutsu shortens her lifespan as well, due to the Hayflick limit.
    • Lady Chiyo's clan dabbles with using chakra "strings" to control life-size puppets (and in some cases, assist a human by adding their reflexes to the subject's). They began work on Kishou Tensei, a jutsu to truly breathe life into puppets, but stopped when they discovered it had a nasty side-effect of (you guessed it!) killing the user. It turned out Kishou Tensei could heal almost anything, including otherwise lethal injuries and even death. Unfortunately, to do so, it used the life energy of the user, along with their chakra, so using it even in the normal way would be highly taxing for the body. And if they used it to revive someone who died, they would die in their stead. Chiyo winds up using it to resurrect Gaara after his death due to Shukaku's removal.
    • Those with the Rinnegan can use a similar and jutsu to Kishou Tensei, but much more powerful, Gedō: Rinne Tensei/Outer Path: Rinne Rebirth. It is capable of resurrecting large groups of people at once, at the cost of the user's life. Nagato used it to revive those he killed during his assault on Konohagakure, dying in the process.
    • Pain has been shown to have an incredibly powerful version of his Shinra Tensei/Almighty Push that takes off years of his life, but can destroy an entire city in one blast. And he uses it on Konoha. Nagato, on the other hand, is an Uzumaki, which means he has his clan's longevity, so he can use it with reduced risk.
    • The Shiki Fujin/ Reaper Death Seal summons a Shinigami, who takes both your soul and your opponent's and forces them to fight forever in its stomach. The Uzumaki created a mask that allowed one to free the consumed souls, but it required its wearer to commit Seppuku to do so.
    • The Mangekyou Sharingan is an enhanced version of the Sharingan that grants all manner of nifty new powers like Tsukiyomi, Amaterasu, Susanoo, Kamui and Kotoamatsukami, but each use of said techniques causes the user to slowly go blind (which eventually removes the ability to use said techniques entirely) and rapid and continued use accelerates the process. Sasuke only had his for a matter of days at most before his constant and reckless use almost blinded him literally. The only ways to avoid this are to upgrade to the Eternal Mangekyou Sharingan, which requires obtaining a close relative's Mangekyou Sharingan to replace your own, as Madara and Sasuke did, or have Hashirama's Senju cells to regenerate the deterioration, which is what Obito relied on with his remaining eye.
    • Izanagi allows users to cast genjutsu on themselves that can briefly override reality. As a tradeoff, the eyes used to cast the genjutsu will be permanently blinded. The only workaround to this seems to be 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,Izanami, which trapped its target in a Stable Time Loop until tey accepted the outcome they were trying to avoid. Even Edo Tensei-revived shinobi aren't immune to the blinding, as Itachi showed
    • The cells of Hashirama Senju, the First Hokage are both this and a potential Deadly Upgrade. They give those who are spliced with them a tremendous Healing Factor, capable of regenerating missing limbs and otherwise irrepairable organs, like the eyes. They also give those with them the ability to use Hashirama's one-of-a-kind Kekkei Genkai, Mokuton/Wood Style. Unfortunately, the sheer vitality of his cells could overwhelm their user if they overexerted of were simply incompatible, turning them into trees. Orochimaru once experimented with 40 children by injecting them Hashirama's DNA, and all but one of them became trees sooner or later. The Sole Survivor was Yamato.
    • The Eight Inner Gates (as referenced in the page quote) is a technique that grants exponentially greater strength as each gate is opened, but with increasing strain on the user's body; Rock Lee was almost permanently crippled by using five of them. If all eight are opened, the user becomes physically stronger than any human could be for a few minutes, though the cost of this is dying shortly after. When Guy uses all eight gates he becomes more powerful than even Madara Uchiha, who was hosting the Juubi to boot, after which his body is so overheated that it starts dissolving into ash while he's still alive. Naruto stops him from dying, but he's still in a wheelchair years later, as trying to use the leg he nearly killed Madara with causes him extreme pain.
    • Chouji's clan have three Food Pills that each boosts their Chakra massively but have worsening side effects with the final one being fatal due to converting all of their fat cells into Chakra. Chouji survives thanks to Tsunade and a Nara clan medical book.
  • Inuyasha can allow his demonic blood to temporarily dominate him by casting aside Tessaiga (or having it stolen); it's a form of Superpowered Evil Side. This "demon form" makes him a lot stronger, but his soul decays with each use, and he becomes more bloodthirsty, vicious, and indiscriminate the more his demon side takes over. It also becomes easier to activate (but harder to turn off) over time, implying that his demon side will eventually take over completely if he keeps using it.
  • Bakugan
    • The Ability-X Cards, which force an unstable super-powered evolution on the Bakugan they are used on. In return, the amount of power can become so great that it drives the Bakugan insane, and if allowed to grow even further, can cause the Bakugan to explode.
    • The Bakugan Linehalt was imprisoned during his early life due to being last of the Dark Bakugan, a tribe that possessed an ability known only as the forbidden power, but he had no idea what the forbidden was actually was or how to use it. When he finally unlocks the forbidden power, it turns out to be an uncontrollable World-Wrecking Wave that the user can't stop once they have activated it and he would have unwillingly destroyed the planet he was on if he hadn't been stopped by Dragonoid Colossus intervening. He refuses to ever use it again until he figures out that it can also be used to heal, turning it into a World-Healing Wave.
  • Rurouni Kenshin:
    • Kenshin fighting style, Hiten Misturugi Ryuu, has an ultimate technique that involves putting the user in significant danger. If you hesitate for even a moment, you either die or lose your leg. If you don't hesitate, you might still lose your leg. But overall, the style as a whole takes its toll on Kenshin, who winds up having to retire from swordsmanship for good. Shishio used this technique as well, and as he was in a full-body bandage, he died of heat exhaustion after 15 minutes.
    • Sanosuke's Futae No Kiwami becomes one over time due to its overuse. His hand injury was said to be even worse than the damage Kenshin suffered against Shishio. Though his hand never really heals, he finds ways to minimize the damage.
  • Dragon Ball Z:
    • Goku first learned the Kaio-Ken from Kaio-sama/King Kai, a technique that amplifies all of the user's abilities far beyond their natural limits (not just strength, but vision, taste, hearing, etc). On top of that, it can be stacked, applied multiple times to further multiply its effects up to 20 times. The downside is that it places severe strain on the body, risking severe injury or even death the more it's used. Kaio-sama/King Kai warns Goku to never do more than double it. Vegeta proved to be the Godzilla Threshold where Goku used it at triple capacity, which hurt like hell, and then quadruple during the Beam-O-War. After that, Yajirobe made him scream in agony just by patting him on the back. By the time he fought Freeza, he was strong enough that he could use the lower levels without any strain, but Freeza was strong enough that he had to multiply it by twenty — the maximum. Not only was it not nearly enough to win, it also left him exhausted and defenseless.
    • Thats not even mentioning the Super Kaio-Ken, which was seen only once during his filler arc battle again Paikuhan/Pikkon (though it is mentioned again in Dragon Ball Super). This technique is so dangerously impractical that it results in instant death if used while alive, and Goku can't even use it again, even while dead. This anime-only usage was the last time it was used in Z, as the various Super Saiyan forms had superseded it in nearly every regard, and combining the two was only practical while dead.
    • Tenshinhan's forbidden technique is the Kikoho/Tri-Beam, which will kill him with overuse or otherwise exhaust him to the point of being unable to fight. The attempt that killed him was an attempted Roaring Rampage of Revenge against Nappa that didn't work (mostly because Tien had also lost his right arm and a lot of blood, thus a lot of his strength) and the attempt that drained him to the point of exhaustion was using it over and over in the stronger Shin Kikoho/Neo Tri-Beam format to keep 2nd Form Cell from chasing after Android 18.
    • The Mafūba/Evil Containment Wave is the technique Master Mutaito used to seal Great Demon King Piccolo. It requires so much ki that it kills the user, as it did to Master Mutaito; when Piccolo comes back, Roshi tries it unsuccesfully and dies as well. It turns out age and the low amount of ki most humans have may have been a factor; Tenshinhan survived trying to use it, although it still left him completely defenseless.
      • The Mafuba is brought back (like many old attacks and characters) in Dragon Ball Super in an attempt to seal an immortal god, Future Zamasu. None of the characters even mention the possibility of it being lethal and it in no way weakens the character who used it (except in the manga). It's likely that it was fatal for the Muten Roshi back during Dragon Ball either had too low Ki, he was too old and frail despite his expanded lifespan, or a combination of the two. It was more likely the former as, when the Muten Roshi is brought in for the Tournament of Power, he pulls it off three times in a row, then two more times later on before he decides to quit. Despite being over 20 years older, his ki had increased greatly, matching that of base form Goku.
    • Vegeta has an "Ultimate Final Skill", effectively a Suicide Attack. (Of course, it doesn't work on Buu.) In the games, it's called "Final Explosion" and reduces you to a single hit point. In Super, he eventually improved it so it wouldn't kill him, but still left him too weak to fight effectively, leaving him as easy prey for Jiren.
    • Dragon Ball Super gives us Goku's "Super Saiyan Blue Kaio-Ken", where he uses Kaio-Ken while in his Super Saiyan Blue form. It provides a massive boost to Goku's power, but has a scant 10% success rate and can potentially kill Goku instantly the other 90% of the time. The technique also leaves Goku weakened, in pain, and unable to effectively use his ki afterwards. Like with the original Kaio-Ken, this handicap is either dropped or overcome as Goku uses it more frequently in future arcs.
    • In the Tournament of Power arc, Basil has one in the form of a Power-Up Food that greatly bulks him up, increasing his abilities exponentially, but also eats away at his stamina, causing his body to seize up and collapse from fatigue after just a few minutes.
  • Eyeshield 21:
    • The "Devil Bat Ghost" technique causes tremendous strain on the user's knees. Hiruma orders Sena to seal the technique from view; Sena originally thinks it's to stop the competition from seeing it, until he breaks the order and finds out firsthand.
    • The "Devil Bat Dive" is a rarely-used two-point conversion technique that requires the runner to leap over both lines, spin, and fall into the end zone, carrying significant risk of injury. Most teams don't bother and just kick the extra point. It's rarely used in real life for the same reason.
  • One Piece:
    • In general, any ability gained by Devil Fruit is a dangerous technique. While some have specific drawbacks, they all share one: the user permanently loses the ability to swim. Considering that this is an Ocean Punk series, that's a potentially lethal side effect. Many pirates are aware of this and use the stuff anyway.
    • Trafalgar Law's Devil Fruit, the Op-Op Fruit, allows the user to perform an "Immortality Operation" on a single person. It grants the target eternal youth, but it costs the user his own life.
    • The Alabasta arc introduces Hero Water (or Fatal Elixir), which massively increases all the drinker's physical abilities for five minutes before killing him.
    • The Skypeia arc introduces the Impact Dial, which absorbs any force that strikes it and deals it back to the attacker, but also causes a great deal of pain to the wielder's arm. Its cousin, the Reject Dial, multiplies the counter-force by ten. Wiper, a character intent on killing the Big Bad of that arc with the Reject Dial, uses it three times and escapes alive despite massive damage.
    • Luffy's "Gear" techniques are his Super Mode, and they all qualify.
      • Gear Second allows Luffy to use his legs as a pump to accelerate the blood flow around his body, dramatically increasing his strength and speed. It would kill a normal human, but Rubber Man Luffy can handle it, although it does affect his lifespan. Luffy's a Determinator, though, so that doesn't stop him that often.
      • Gear Third is the next level up; he blows air into his bones, which enlarges his body and makes him that much stronger. However, after only a couple of attacks, the effect would wear out, the air would leave his body, and Luffy would now be Chibi-fied and vulnerable. He learned how to avoid that after the Time Skip, which introduced...
      • Gear Fourth, where he inflates his muscles rather than his bones and augments his whole body with Armament Haki. This is much stronger than ever Gear Third, and he can even use it to fly. But like Gear Third, it has a time limit, after which Luffy becomes vulnerable and cannot use Haki for ten minutes.
    • Chopper's Monster Point form comes from overuse of the Rumble Ball, which allows him to expand his Multiform Balance to seven forms rather than the standard three. The Rumble Ball's effect is already only three minutes, and he can have only one every six hours. If he uses two, he loses control of his transformations. If he uses three, he activates Monster Point, which turns him into an indiscriminate berserker who could curb stomp either his enemies or his allies. It's also potentially fatal and knocks Chopper out of commission for a while, although he gets a better handle on it post-Time Skip.
      • To be more clear: post-Time Skip, just eating one Rumble Ball triggers Monster Point, but Chopper stays in full control the entire time. However, the form automatically deactivates after three minutes, after which Chopper is unable to move for a long time.
    • Rob Lucci's Rokuogan (or Six King Gun) strikes his opponent with a shockwave comparable to that of a Reject Dial, but using it expends a ridiculous amount of energy. Overuse of the technique was enough to give Luffy a narrow window to defeat him.
    • The Energy Steroids from the Fishman Island arc give the user extreme power, endurance, and stamina, but at the expense of his lifespan and possibly his sanity as well.
  • Bleach:
    • Ichigo's fight with Byakuya woke up his inner Hollow enough for it to want to begin taking over his soul. The more he used his power, the stronger the Hollow became. He eventually learned how to master the hollow, which increased his power in battle. However, it could still take over when he was very close to death, resulting in a truly ghastly outcome for everyone involved. Only when he learned Final Getsuga Tenshou, which was another example of this trope that destroyed his power after use, was his Hollow fully mastered.
    • In his battle with Mayuri, Uryuu activated Letzt Stil, considered the last resort of the Quincy. His grandfather had taught him the technique with the stipulation that he should never use it until he found something he was willing to give up his power to protect. Uryuu chose to use the technique prematurely, found out that It Only Works Once, and lost all his spiritual powers. His father Ryuuken turned out to have an even more forbidden technique that could restore Uryuu's powers, but it was a very brutal process. In the Thousand Year Blood War, we learn that there is a way to obtain Letzt Stil powers without the one-time-only drawback, but it is forbidden to traditionalists like the Ishidas as unethical.
    • Certain Kidou are forbidden. Tessai was exiled with Urahara for using a forbidden Kidou that manipulated space-time. Yamamoto used a forbidden sacrificial Kidou, trading his left arm for a massive pillar of fire in an attempt to kill Aizen; as an atonement, he never re-grew it.
    • Captain Komamura's clan has the Human Transformation Technique, which turns them from anthropomorphic wolves into full humans with a power boost. It requires literally giving up your human heart, and when the technique runs out, leaves the user as a full non-anthropomorphic wolf.
  • Towards the end of the Chimera Ant arc of Hunter × Hunter, After his mind finally breaks after finding out Kite was Dead All Along, Gon forced himself to grow by Restricting almost all of his inborn talent to age himself to his physical prime, becoming as strong as Meruem himself to kill Neferpitou in the most brutal and horrifying way possible. By the time he was done with them, Pitou was a burnt pile of purple paste, and Gon nearly exploded, ending up in a coma and with a missing arm. Although Gon miraculously recovered from the nearly-lethal strain his body was put through thanks to Killua and Alluka/Nanika, arm and all, he's been effectively Brought Down to Normal, and he can't see nor use Nen anymore.
  • Yu-Gi-Oh!:
    • Industrial Illusions has the decidedly odd practice of designing cards "too powerful and dangerous to be used," requiring them to be sealed somewhere or guarded to keep them from falling into the wrong hands. They always fall into the wrong hands. (It's little wonder why the game is such Serious Business in this series.) Yugi himself seems to be the only one who recognizes the potential danger of these cards; the first thing he says upon winning Osiris from Strings is, "I must be very careful with this."
    • Yu-Gi-Oh! GX has the "Cyber Legacy", which Kaiser Ryō inherited. Normally, he and the other duelists in the Cyber-Style dojo (yes, the Legacy is apparently so powerful, you need to train in a dojo to properly duel with it) practice the normal Cyber-Style, but there's another set of cards known as the Cyberdark-Style that's sealed away from even the Legacy's heir due to its immense and dangerous power. Ryo learns just why it's so dangerous and forbidden the hard way.
    • In the real game, cards deemed too powerful are forbidden from official tournaments. Unfortunately, they're not always consistent as to what exactly is "too powerful".
  • Ranma ½:
    • Ryoga Hibiki's "Shishi Hōkōdan" is a Ki Manipulation fueled by the user's depression and melancholy. Ryoga tries to increase its power by becoming even more depressed. Ranma tries this when fighting him but eventually sees the flaw in this strategy — the winner of the fight will be happy enough to depower it — and thus creates a much safer (but just as powerful) technique based on boundless confidence.
    • Genma developed two such techniques: the Yamasenken and Umisenken. Unusually for this series, they're both lethal and can be used for ripping out an opponent's heart, strangling him, or cutting him into itty bitty pieces. Genma was loath to teach Ranma anything about them, on the ground that they were far too dangerous; he only acquiesced when he learned that Ryu Kumon was using the Yamasenken. Ranma duelled Ryu with the stipulation that if he won, Ryu would seal the techniques forever.
    • Parodied with Happosai's "Happo Fire Burst", which was sealed away for being too destructive... when he accidentally burnt up a recently-stolen brassiere with it. He unseals it to punish Soun Tendo and the Saotomes, when it turns out to be nothing more than a fancy name for throwing homemade firecracker bombs around (which is no less effective).
  • Outlaw Star's Caster gun fired spiritual Caster bullets. Each type was represented by a number, although their differences were never fully established. Eventually, Gene realizes that three numbers never come up, so he tracks down the gunsmiths who make these bullets. They each give him one, but they explain that since they draw on the gunner's soul (there being so little mana left in the universe), if he fires all three, he will die. Sure enough, he needs all three, and sure enough, he dies along with his enemy, but he was in the Galactic Leyline, which noticed that everyone inside was dead and performed an Auto-Revive.
  • Almost everybody in Get Backers has one. Ginji starts going crazy if he is in his Lightning Emperor mode for too long. Ban can only use his Jagan three times a day, once per person per day. Himiko's acceleration perfume strains her body. Juubei's Black Flying Needles are controlled by a large magnet, and the force of the magnetic field wreaks all kinds of havoc on his body and blinds him early on.
  • Late in Tekkaman Blade, D-Boy finds that the Tekkaman transformation is slowly destroying his body. Later, he apparently gets better by "evolving" his transformation into the more powerful Blaster mode. Unfortunately, that turns out to be a better example of this, since now he's losing memories whenever he transforms, which for him is even worse.
  • Mahou Sensei Negima!'s version of Black Magic seems to act like this. The first time we see it used is when Jack Rakan demonstrates it for Negi and nearly kills himself in the process. Negi then starts undergoing training so that he'll be able to use it safely. We don't see the real direct consequences of Dark Magic, though, until Negi basically overdoses on magic and is forced to fight his Enemy Within; even if he wins, he won't exactly be human anymore.
  • In Slayers, Lina's Giga Slave is the mother of all Dangerous Forbidden Techniques. It consists of summoning a fragment of the Lord of Nightmares into the physical plane, so not only will she die if it is miscast, but she'll take the entire universe with her. Naturally, it's miscast, and only a literal Deus ex Machina on the part of the Lord of Nightmares saves the day. Ragna Blade also consumes magic quickly enough to put the caster's life in danger if they try to maintain it for too long.
  • Parodied in The World God Only Knows: Suffering from Dating Sim withdrawal, Keima resorts to "Capturing God Mode" in order to clear his backlog, playing six games at once at blinding speed while still able to react emotionally to each one. He claims that an hour will cause the use to lose three years of his life (or at least be tired enough to feel that way). He eventually passes out under the strain. That doesn't stop him from hitting 24 games at once later in the series.
  • It's revealed in Magical Girl Lyrical Nanoha StrikerS that Starlight Breaker causes considerable strain on Nanoha's body, and that her constant usage of it, as well as her tendency to use Deadly Upgrades, contributed to her being critically injured and hospitalized for nearly a year.
  • Jin from Samurai Champloo learns his master's Dangerous Forbidden Technique only by word of mouth, along with (needless) explanation of its danger. During his final episode duel, he has to use it in battle. He allows himself to be stabbed, and takes advantage of his opponent's position at his side and effective defenselessness (as his sword is stuck in Jin) to strike him down.
  • Zoids: New Century has a mecha version: Among the three alternate armours available for the Liger Zero is the Panzer armour, effectively turning the Liger into a walking tank with huge guns and lots and lots of missiles. However, it's so heavy and power-consuming that the Liger can barely move and quickly overheats just from wearing the armour. It has to be ejected on the battlefield right after each use to avoid melting the Liger Zero.
  • In Soul Eater, using Tsubaki's Uncanny Sword mode takes a toll on Black☆Star's health. Early on, he can only maintain it for a short duration before passing out. At one point, the normally submissive Tsubaki refuses to use it out of fear for her partner's well-being. Eventually, he finds a way around this, at which point the mode apparently stops having a dangerous effect. Really, all it needed was for Black Star to listen to others (namely Tsubaki) in order to have a chance of working out the technique, rather than assuming it took only physical strength. Being a decent guy really, he manages it.
  • Sailor Moon:
    • Sailor Pluto will die if she uses her power to stop time, and Sailor Saturn will die if she uses her power of destruction. They're forced to break this taboo in the various series — in the manga and Sailor Moon Crystal, Pluto breaks her taboo to stop Prince Demando from colliding the past and future Silver Crystals and causing a Time Crash while in the original anime, she breaks the taboo to allow Uranus and Neptune to enter Mugen Academy and reach Mistress 9 before their helicopter is destroyed; in all three incarnations, Saturn uses her power to stop Pharaoh 90 and allow Sailor Moon to restore everything. In the manga and Crystal, Pluto ends up being reborn as Setsuna Mei'oh and returns to action during the Infinity Arc while the original anime her fate is left ambiguous and she sits out Super S; Saturn is reborn as a baby in all three versions and doesn't return until the final arc with Pluto.
    • The anime gives us the Silver Crystal, which at full power equates to a Kamehame Hadoken and kills the user nine times out of ten. But they get one lash wish, which is usually enough to reverse it; Moon got her normal life back and it was enough for her, Mamoru and the Senshi to be revived, even if with Trauma-Induced Amnesia until some time later.
  • The Rising of the Shield Hero: The Cursed Series is quite powerful, although it requires an adequate sacrifice in using its power as its name implies. The most notable attack is Naofumi's Blood Sacrifice that absolutely ensures it utterly destroys an enemy, if not bring them to near-death. Unfortunately, as the name of the attack implies, it expels blood from multiple areas on the user's body in order to act as the "payment" required for using said skill as it acts as the medium to use said skill, and if the user is not treated immediately after, he/she will most likely die and if they survive then he/she will be inflicted with a temporary curse that sharply debuffs his/her stats.
  • In Yu Yu Hakusho, Hiei's Dragon of the Darkness Flame is an absurdly powerful technique that summons a dragon made of insanely hot hellfire that incinerates pretty much any enemy that comes into direct contact with it, even fire-resistant demons. The catch? If the user isn't sufficiently powerful, the dragon can turn on the caster and devour him. And the first time Hiei used it, he had to offer his right arm as a sacrifice. Also subverted, as the one moment the attack is turned on Hiei, he's become powerful enough to control it, not only surviving, but also temporarily absorbing it into his body, becoming much, much more powerful.
  • Black Cat:
    • Train can only use railguns five times per day. In the final battle, he squeezed out a sixth shot, resulting in him unable to perform it anymore. He's not worried, though, since he has already taken care of the Big Bad.
    • Sven's eye ability makes him very tired after using it, which limits him as well, though his ability isn't near as badass.
  • Parodied in Ninja Nonsense, where the technique that has been "banned ten years ago because it was so dangerous" is duct tape underpants.
  • In Code:Breaker, Toki Fujiwara's usage of his Gauss Cannon will damage whatever arm that he uses to fire. This means he can't fire more than twice overall in a fight.
  • Overuse of power in Giant Robo can lead to nasty consequences. A mook burns himself to near-ashes with his pyrokinesis trying to keep his buddies warm, Alberto the Shockwave breaks apart after absorbing the Monster Sphere's energy field, and several characters' powers run fatal risks.
  • In Fullmetal Alchemist, human transmutation is the sole taboo when it comes to performing alchemy, and rightly so. The law of equivalent exchange is strict — you must sacrifice equal or greater value, and the value of a human life places a horribly high toll on anyone who would dabble in such a practice. While trying to resurrect their mother, Edward lost a leg and Alphonse lost his entire body. It cost Edward his arm to merely tether Alphonse's soul to a suit of armor in a golem form through a blood seal. And that still wasn't enough for the alchemy to work. Not that it matters as Ed later learns that human transmutation can't bring the dead back to life; what they brought back was not their mother as it had black hair instead of brown, the limbs are too long and the pelvis belongs to a male. But it does give him the hope that Al can get his body back.
  • Saint Seiya:
    • Dragon Saint Shiryu is warned by his master never to push his fighting technique beyond a certain limit, lest he unleash the "Ultimate Dragon", basically sending himself and his opponent into orbit. Of course, Shiryu does end up unleashing the "Ultimate Dragon". But he doesn't die. His opponent Shura has a last-minute change of heart and manages to send him back to Earth with just a very well-timed kick. Seriously. That being said, the technique was never used again in the manga. In the next arc of the anime, Shiryu attempted it again as a last resort move, but stopped when doing so would destroy a MacGuffin that was needed.
    • Athena Exclamation is a technique so devastating, so powerful, it has the power to annihilate the Earth. Therefore, it was declared taboo by Athena's Saints. It consists of three Gold Saints focusing all their Cosmo into a single point, discharging a blast with the same power as the Big Bang itself. Naturally, it was used in the final arc. And once that taboo was broken, it was used twice more — by two opposing trios of Gold Saints.
  • In Inazuma Eleven, Teikoku has some hissatsu techniques, explicitly called "forbidden techniques", which are extremely powerful but strain the user's body; a single use is enough to cause searing pain, and three uses in a single match is liable to send the user to the hospital with the possibility of permanent injuries.
  • Everyone seems to have one in The Prince of Tennis: Tezuka Phantom and Zero Shiki Serve, Ryoma's Cyclone Smash, Atobe's Tannhauser Serve, Sanada's Rai, you name it. The most powerful, though, is "Dash Hadoukyuu", Kawamura's most powerful shot until Final Hadoukyuu. The original Hadoukyuu already puts a great deal of strain on the arm, while the Dash Hadoukyuu is restricted to once per match. Naturally, he breaks this rule against Gin Ishida.
  • In Mobile Suit Gundam MS Igloo, the EMS-10 Zudah was a powerful (for its time) Zeonic Mobile Suit with just a teensy, tiny little flaw - overexerting the engine would cause the Mobile Suit to fly apart. Oh, sure, by revving those engines, you'd get an incredible speed boost, but it's usually not worth losing your life over it.
  • The NT-D ("Newtype Destroyer") system in Mobile Suit Gundam Unicorn. Built in to the eponymous Gundam, the system activates if it detects a Newtype (or cyber-Newtype) somewhere in the vicinity. It then releases all of the limiters on the Gundam's systems, directly linking all the suit's functions to the pilot's mind. This allows the pilot to gain extreme reflexes, almost mechanical precision, and even the ability to hijack Psy-Commu weapons, which are generally a Newtype's most dangerous weapons. However, this system can override the pilot's own morals with the system's programming to destroy Newtypes, and runs a very real risk of burning out the pilot's mind and causing severe brain damage.
  • In Mobile Suit Gundam AGE, Kio views the AGE-FX's FX-Burst Mode as one, as he has recently made the switch to technical pacifism, and he can't use the precision weapons necessary to guarantee the safety of enemy pilots while using that mode.
  • Gundam Build Fighters Try has "assimilation", a not-very-well-explained phenomenon where a pilot apparently links his mind to his Gunpla, controlling it like his own body and greatly increasing its performance. Downsides? The pilot incurs actual, physical injuries when the Gunpla is damaged, and on top of that, using this ability is exhausting in the extreme. There is a real risk of receiving permanent or even life-threatening injuries from this, in a sport that's supposed to be completely harmless (at least, to the people playing it).
  • In Mobile Suit Gundam: Iron-Blooded Orphans, it's possible to overclock a Gundam's Ālaya-Vijñāna System to dramatically increase the suit's performance and reaction time, but the mental overload from doing so renders the pilot unable to use one or more bodily functions ever again, unless they're connected to the machine. Gundam Vidar avoids these drawbacks by using the Ālaya-Vijñāna System Type-E, which passes the mental strain onto an AI based on Ein Dalton's brain, which then controls the pilot's body to move the machine.
  • In Bamboo Blade as well as real-life Kendo, the throat strike is treated this way, because of the high risk of seriously injuring your opponent if done incorrectly. In the series, it is used mostly by morally ambiguous or outright villainous characters, although the main protagonist Tamaki will also attempt to use it when sufficiently provoked or against an especially skilled opponent. In real-world Kendo, throat strikes are only permitted to be used only by high-ranking Kendoka.
  • In Raideen, the titular mecha has the powerful "God Voice" attack, which ends up ruining his vocal cords every time he does it. In the Super Robot Wars games, Akira will actually end up being unable to speak if you use this too many times before a certain point.
  • Few would expect this from an anime about the circus, but the arc of Kaleido Star revolved around one of these. There was a Dangerous Forbidden Technique for trapeze and highwire artists, the Fantastic Maneuvre, which was so dangerous and forbidden, Fool refused to even tell Sora what it was because as soon as she heard about it, she would be so obsessed with it that she'd try it even when she wasn't ready, and die. Attempting this Dangerous Forbidden Technique was what killed Karlos' best friend and old partner Aaron Killian, becoming His Greatest Failure and turning him into The Atoner. And it drives Aaron's son Yuri to seek revenge against Kalos, taking the Stage away from him because he believes he drove his father to basically kill himself. Needless to say, by the end of the first part of the series, Sora and Layla perform it successfully. Doing it even once is enough to cripple an already injured Layla for life and end her circus career forever.
  • Parodied in Daily Lives of High School Boys High School Boys and the Sure-kill Shot skit, when Mitsuo claimed he "sealed" his "reflection shot" because it's too unfair. He's right; the soccer ball reflects because of the piece of plastic he planted on the field. Mitsuo being Mitsuo, it still got saved by the self-proclaimed Non-Action Guy Hidenori.
  • Being a Deconstruction of the Fighting Series Played for Laughs, Muteki Kanban Musume parodies this trope when Kankuro tries to decide what thing he would imitate to beat Miki.
    Kankuro: As long as I imagine myself as something before training, I’ll gain both confidence and strength, nya. What should I imagine myself as next, nya?
    Akihiko: Shouldn’t you have already decided on that?
    [Flashback of Miki being Curb Stomp Battled by her mother, a fat restaurant hostess.]
    Kankuro: That’s impossible, nya.
  • In Den-noh Coil, there's Imago, which allows the user of it to effectively become a Technopath within the augmented reality. However, side effects of using it result in damage to one's body, including heart problems and other nasty effects.
  • Rebuild of Evangelion brings us Beast Mode, which grants the Evangelion a power boost at the cost of potentially contaminating its pilot's mind. It's also shown to be a very Painful Transformation, for both the Eva and the pilot. Further, even if it is successfully activated, the pilot loses all reason and is only capable of fighting like an enraged animal.
  • In Unlimited Fafnir, Yuu is able to obtain tremendous power from an ancient dragon calling itself "Yggdrasil" in order to defeat dragons attacking humanity. Unfortunately it requires his memories in order to summon said powers.
  • High School D×D gives us Juggernaut Drive, which allows the users of Boosted Gear or Divine Dividing to completely unseal the Dragon contained within, transforming into a near-unstoppable, monstrous form that goes on a berserker rampage until the user's life is consumed. Both Issei and Vali have to find a way around this. Vali has, long before the start of the series — as a Born Winner, he has a stupid amount of Devil-power and fuels his JD with that instead of his lifeforce. Issei forgoes the form entirely in favor of creating Cardinal Crimson Promotion, an exhausting but near-equal power boost that relies on his link to Rias, befitting his role as The Champion.
  • In both Getter Robo G and its expy Gekiganger 3, the Shine Spark and the Gekigan Flare are forbidden, as the three pilots have to hit a switch at the same time to activate the attack or risk destroying the robot.
  • Fairy Tail
    • Summoning the Celestial Spirit King is this. The Celestial Spirit King is the most powerful spirit a celestial mage can summon, so powerful in fact that just his appearance counts as an attack! To do so requires a ton of prerequisites, these include:
      • Having a very high magical energy threshold, usually sufficient to be able to summon and maintain three Celestial Spirits at once, a feat considered even by the spirits to be dangerous for most Celestial Wizards. After the summoning is done the user, if not outright killed by summoning the King due to magical exhaustion, will still be physically incapacitated due to the strain the summoning magic causes.
      • The Celestial Spirit user has to sacrifice one of the Twelve Golden Keys to the Zodiac. These keys are super rare as only one key can be in existence on the planet at any time. While the keys do regenerate in time, there's no controlling where it might end up and since the contract is broken, it's up for grabs.
      • The User has to have a strong emotional bond with whatever key they sacrifice. Otherwise the summoning will completely fail! Lucy was in such an emotional state that right after summoning the king her response by one of the demons as to what she had done is to cry uncontrollably and not answer!
      • Even if the summoning IS successful the King is under a very strict time limit. Typically only about 10 to 15 minutes depending on the mage's magic power and his emotional state is directly tied to the mage's emotional state. So if the mage is incredibly upset or angry the king might very well go on a berserker rush against his opponent. This is exactly what the Celestial Spirit King does in response to Lucy being so upset.
    • In the sequel series, the Fifth Generation Dragon Slayers (Dragon Eaters) have the ability to activate Dragon Force at will, boosting their powers to levels such that they can overpower even another Dragon Force wielder. However, it's use is strictly forbidden by their guild because it accelerates the process of Dragonization and permanently turns them into dragons, oftentimes turning them into mad beasts that need to be put down.
  • Bakugan has the forbidden ability card Chaos X, which can give a Bakugan More Dakka (albeit resulting in death in some cases) and force them to evolve, at the expense of their souls.
  • Gargantia on the Verdurous Planet has a Brain–Computer Interface between Ledo and Chamber, which will kill Ledo after a certain amount of time. Normally regulations won't even let Chamber activate it without knowing that Ledo will have access to Galactic Alliance medical personnel immediately afterwards. Ledo uses it in the final episode to keep up with Striker, but ultimately, Chamber ejects him and chooses to make a Heroic Sacrifice himself.
  • In Yuki Yuna is a Hero there's the Mankai, a Super Mode the Heroes can activate to channel the power of the Shinju itself. However, it comes at the cost of a sacrifice, namely, one of the Hero's bodily functions, such as the loss of the sense of taste, voice, or ability to use a limb.
  • Chuuya's "Corruption" in Bungou Stray Dogs allows him to manipulate gravitons, turning him into an incredibly powerful combatant with Super Strength and the ability to throw miniature black holes. The downside is that he also enters an Unstoppable Rage which forces him to keep rampaging until he dies of exhaustion. For this reason, he only uses this technique when he's confident that Dazai will be there to use his Power Nullifier ability to stop him once the task is done.
  • Part of Izuku's Character Development in My Hero Academia is to stop treating One For All like this trope. Prior to developing the "One For All: Full Cowl", Izuku would pour his power into one extremity, which would deliver devastating blows at the cost of wrecking that extremity. It got to the point where resident healer Recovery Girl put her foot down and refused to treat any One For All user because of their recklessness. Under "Full Cowl", he instead focuses that power through his entire body and draw out a certain percentage so he isn't wrecking his body. It's still this trope if he goes over a certain percentage, though.

    Asian Animation 
  • In Tobot, Tobots X and Y are able to combine their powers to use an ability called the Combo Shield, which creates a protective barrier as suggested by its name. Using this power drains X and Y's energy quickly.

    Comic Books 
  • In the Marvel universe, there exists a weapon called the Ultimate Nullifier which can Ret-Gone anyone or anything the user chooses. But if the user doesn't visualize the target properly, then the user is erased. This is possibly the only weapon that can truly defeat Galactus. (Possibly. He is known to be afraid of it, at least. Whether any mortal would actually be capable of perfectly visualizing Galactus is dubious. However, in his, and its, first appearance, he worried more that Reed would unmake the whole universe trying, and he immediately decided to leave Earth alone.)
  • The "Demon Ball" technique in Bowling King. Its creator injured himself badly attempting to perfect it and was forced to retire from professional bowling.
  • In the Buffy the Vampire Slayer prequel comics, there are dark magicks that the Watchers are forbidden to use. Someone does it anyway and gets revealed by Giles. But Giles had also used a forbidden technique to reveal the guy, which is why he gets put through a torturous test that either drove everyone else who took it insane or killed them outright.
  • The Mighty Thor supporting character Beta Ray Bill is a cyborg whose body was built with safeguards to prevent his internal reactor from overloading. By releasing these safeguards, he can multiply his power by many times. The drawback is that after a few minutes of this, his reactor will reach critical mass, with explosive consequences.
  • The Human Torch of the Fantastic Four can release a blast of nova-intensity heat, which was very dangerous to do in his earlier days (one issue even stated that releasing it at maximum power would instantaneously kill every living thing in the same hemisphere of Earth as him). Later subverted as he learned to control it better, making collateral damage no longer a serious problem.
  • Downplayed by Nightcrawler of the X-Men; he can carry someone else with him while using his mutant ability to teleport, but the strain is, in his words, "murderous", both to him and the passenger. Doing it more than once would likely kill them both. However, this lessens as he learns his powers better. The first time he did it, he screamed in agony and he and his passenger were incapacitated for some time. Now it's something he easily does, though it leaves the passenger disoriented. One of his favorite techniques is to grab an opponent and make several jumps, leaving his opponent to suffer while he remains unharmed, though he still must take care not to exhaust himself when doing this. A sufficiently tough opponent can be left unharmed while the strain of multiple jumps continues to add up and do him more harm than the enemy
  • When put into a situation where there's nothing around that he can manipulate with his magnetism abilities, Cosmic Boy can use the iron in his own body. This is understandably dangerous, painful and usually very limited, but he can usually find something else to use since villains tend to underestimate just how little he needs to work with.

    Fan Works 
  • A Growing Affection has a few:
    • Naruto's original technique, the Blood Clone Jutsu uses blood to form clones almost as tough as the creator, that return any leftover chakra to the original when the technique ends. But the amount of blood required means that anyone without a healing factor would pass out creating more than one Blood Clone. Naruto creates a stronger version that has Sakura and Ino heal him and give him plasma pills so he can make a small army of blood clones.
    • Breaking the Souhi is not unlike the retributive strike below, it (according to lore anyway) instantly reduces the temperature of everything in a five-kilometer radius to -100 degrees (Fahrenheit or Centigrade not specified), including whoever breaks it.
  • Ancient Sins has a few moves and spells that aren't forbidden, but have disasterous consequences if over used. Dante's most powerful spell is Divine Etherno, Roaring Nebula, but it fully drains all his power and could possibly kill him. Equine Rarity learns how to increase her blood flow, which grants a great boost of power, but could rip apart her entire vein system is over used. Lastly, Humane Pinkie Pie can detonate the sugar inside someone's blood and her own, but she will die if she uses it on herself.
    • However, the last one is subverted, becuase Pinkie later becomes strong enough to survive the explosion, but is left comotose for a week.
  • Child of the Storm has wielding dark magic as this - even if you're capable of avoiding the corrupting effects, it has a price, even if you're as skilled and powerful as Albus Dumbledore, who had to delve into the very depths of the Dark Arts to defeat Grindelwald. He refuses to elaborate on just what that price was. And even sociopathic necromancer Gravemoss refuses to pay the price for unleashing some of the stuff in the Darkhallow.
    • In the sequel, Harry using his inner Phoenix fragment qualifies as this on several levels, mainly because it's insanely volatile and unless you're incredibly careful, With Great Power Comes Great Insanity, and you end up becoming the Dark Phoenix, as he does at the end of Forever Red. Plus, there's the fact that it weakens the already very fragile fabric of reality and risks unleashing Surtur, the original Dark Phoenix.
  • Twilight mentions in Getting Back on Your Hooves mentions unicorns have more potential magical power than they can safely use, which operates on the same principle as muscles being capable of far more than they can safely use. Using their maximum power would drastically increase what they can do, but at the risk of damaging or breaking their horn. At the finale, Checker Monarch does this after her Engineered Public Confession in an attempted Taking You with Me on Trixie and the mane cast. It not only fails, but her horn is badly damaged as a result.
  • In Pokéumans:
    • Spiritus reveals to Brandon that as an Energy Channeller he may be able to perform Total Absorption - which would consume the enemy's aura (and by default, is totally fatal) and may even take a hit on his sanity to the point of unleashing a Superpowered Evil Side.
    • Rikuto of the Long Island Elite Four apparently knows many of these but must restrain himself from using because, well, he can't kill all of the base's most promising battlers whenever they fight him.
  • Parodied in a Justice Society of Japan omake, where Mr. Satan and Dan Hibiki both claim to know one of these, but are both too scared to actually perform it.
  • The Legend of Cynder Series: Myst's fury, after she takes a potion to help cure her blindness. The potion has a side effect of drastically increasing a dragon's powers the more they drink; Myst needed to drink a whole bucket's worth to purge The General's poison that was blinding her out of her body. It's heavily implied that Myst's fury would be one of the single most powerful attacks in the entire fic series. However, it would have the unfortunate side effect of killing her if she were to release that much power at once. As such, she has never once used it so far.
  • In Origins, a Mass Effect/Star Wars/Borderlands/Halo Massive Multiplayer Crossover, Dr. Kevin Filner comes up with one. In order to fight 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 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 Jack's students we're talking about, he's probably right.
  • Subverted in the Naruto story Vapors, where the Hiraishin should be this given the numerous ways to Tele-Frag yourself or worse. In fact, it has several safeguards built in to avert this, although using it with cranial hemorrhaging is still a very bad idea.
  • Ranma Saotome, Chi Master has the Black Dragon Breath Technique, which greatly increases the amount of chi the user has at his or her disposal, and automatically channels it into a dragon-shaped battle aura around the user. The drawback is that it puts a lot of stress on the user's body. Since the battle aura is so compact, it eventually causes the user's muscles to tear themselves apart. Even worse, the breathing exercises required to maintain the aura starts rupturing the blood vessels in the lungs after a while, eventually causing the user to drown in his or her own blood.
  • Queen of Shadows: The primary fighting technique employed by Toguro uses chi expand his strength and speed beyond human norms. However, Ikazuki notes that this has the side effect of draining his life force in the process.
  • Parodied in Dragon Ball Z Abridged when Nail suggests to Piccolo to fuse. Nail tells him that the technique is forbidden even with their highest of clans... only for Piccolo to ask if they're just going to abuse it. "Maliciously!"
  • In Pokémon Reset Bloodlines, Z-Moves can only be used once per day because they drain both the Pokémon and the trainer of a lot of energy, and it's known that people have died trying to perform them consecutively within the span of hours. However, Bloodliners seem to be capable of using them consecutively without fatal risks in the span of minutes with different Pokémon, albeit not without collapsing after doing so.
  • In Transcendence, Ichigo's bankai effectively makes him a juggernaut that can go head-to-head with some of Azeroth's toughest entities. However, his vessel can't withstand the strain his power puts on it, so he can't use his bankai for more than a few minutes without risking it causing heavy damage to his body. Even if he doesn't leave it active for long, deactivating it immediately leaves him exhausted. As a result, Ichigo treats bankai as a last resort.
  • Dekiru: The Fusion Hero!:
    • Izuku views Human Fusion as this. While an incredibly powerful technique, it has many downsides. It's Cast from Stamina, with even more stamina being drained when using taxing techniques/abilities like One for All, its Mental Fusion aspect risks revealing personal information and secrets to all component partners, all injuries endured during the fusion will be split amongst every component partner, and it's very unpredictable, as the fusions are entirely his or her own person. Unless Izuku has merged with the component partner before, whichever Quirk the resulting fusion has will be completely unknown until he or she figure it out themselves. As a result, it's best used as a last resort. Aizawa actually praises him for this view, because it shows that he won't be a victim of Crippling Overspecialization, which can be fatal for a hero.
    • Multi-person fusions. While they are more powerful (enough to rival All Might), they drain even more stamina than the standard one-person fusion, especially from Izuku. Using a multi-person fusion for more than once a day can cause potentially fatal exhaustion to him.
  • Truth And Consequences: Wielding the Ladybug and Black Cat Miraculous together is presented as this. In theory, you can become a Reality Warper, capable of making your heart's desire come true. In practice, it requires an incredibly strong will, and perfect spiritual balance. Only one person has ever successfully pulled it off, with the consequences of the failures ranging from turning the wielder's hair orange, to transforming them into a potted plant, to Ret Goning an entire civilization. Marinette is convinced she can pull it off; everyone else, not so much. When Gabriel gets his hands on both, not only does he fail to resurrect Emily, but he himself is seemingly annihilated - taking both Miraculous with him.
  • In both My Hero School Adventure Is All Wrong As Expected and the source material, Tokoyami's Quirk, Dark Shadow, becomes incredibly powerful but also impossible to control in absolute darkness. However, this is Subverted with Hachiman's copied version. Thanks to starting at merely 1/108th the power of the original, pitch-black darkness instead just makes Dark Shadow strong enough to be usable even without prior Stockpiling.
  • The Ultimate Evil:
    • The Book of Ages is graduated from I Thought It Was Forbidden to this. It's rumoured that if the Book is damaged, or if too many inconsistencies are made when its reality-warping power is put to use, the fabric of reality will be destroyed. In The Ultimate Evil, the former risk becomes a reality when the Book gets burned, though Valerie and Shendu fix it before it's too late.
    • In The Stronger Evil, Natalie fears this regarding Valerie's Other-derived powers.
    • Jade taking on Tarakudo's mark, the same as in canon, in the first story. In the second story, she takes on the mark despite knowing the dangers in an attempt to command the Shadowkhan to turn on Tarakudo. A pity she didn't count on Tarakudo speeding up and forcing her transformation back into her Super-Powered Evil Side.
  • In the Avatar: The Last Airbender fanfic Breath Of Life, it turns out that the Air Nomads had a bunch of dangerous techniques designed specifically to kill that were invented by rogue Airbenders. The pacifistic Air Nomads considered these techniques dangerous because their deadliness went against their way of life and had the knowledge locked up. The reason Aang knew these techniques was because he was forced to learn them when the monks found out he was the Avatar.

    Films — Live-Action 
  • The entire point of The Dark Side in Star Wars. The lure of easy power comes at the price of becoming Drunk on the Dark Side. The Expanded Universe defines the deadliest lightsaber style as Juyo/Vaapad, a mainly Sith technique which is extremely aggressive. For that reason, it's forbidden to most Jedi except those who demonstrate they're capable of handling it safely — i.e., without slipping to the Dark Side. Mace Windu is the creator and supreme master of Vaapad.
    • The Last Jedi reveals that Astral Projection is one such technique for all Force users. As Kylo Ren notes, it's an extremely powerful ability, but the physical strain it causes (especially if done over large distances) is so tremendous that it will likely kill the user. In the climax, Luke uses it to distract the First Order and ensure the Resistance escapes; sure enough, the strain of projecting himself across several light years for an extended period of time kills him, causing him to become one with the Force.
    • The Rise of Skywalker introduces a technique called "lightspeed skipping", a series of brief jumps that Poe uses to pull a Hyperspeed Escape from the First Order. It works, but the Millennium Falcon is on fire when she returns to the Resistance base.
  • In Kiss of the Dragon, Jet Li describes the titular technique as "very secret, very forbidden". The technique actually poses no danger to the user; it is forbidden because of its effect on the target.
  • In Blades of Glory, the Iron Lotus is a figure skating technique developed by the coach in his "wild youth", but only one country was crazy enough to try it — North Korea. The only attempt resulted in the woman's head cut off by the man's ice skate (as impossible as this sounds). According to the coach, the only way for the technique to be performed successfully is by a pair of two men.
  • In Jumper, the teleporting Jumpers can easily move themselves and another person, but greater masses are more difficult. Griffin is able to jump cars and a double-decker bus at one point, but only when they're moving and it's implied he's using their momentum to take some of the strain off; he also relates a tale of a Jumper who tried to teleport an entire building, noting that this Jumper only managed to shake it a little before the strain killed him. In the climax, David manages to jump a sizable portion of his girlfriend Millie's apartment twice without killing himself when he was basically trapped in the apartment by his enemies, but it took a lot out of him.
  • In Highlander: Endgame, the unbeatable sword technique is unbeatable, if both duelists simultaneously block each other's weapons behind their heads as if locking them in place. Even with centuries of sword practice, the results of this technique cannot be avoided. The two combatants cannot simply disengage from combat, slowly making sure their swords are not aimed at each other's necks. It simply cannot happen.
  • In Inception, the "Mister Charles" routine is treated this way. It amounts to an Investigator Impersonation, and Cobb's associates are afraid to let him use it. If it goes right it will help them out of a bind, but if it goes wrong it will be very bad, and Arthur implies this has happened to them in past jobs.
    • Cobb regards the titular concept of "Inception" this way.
  • In Man of Tai Chi, Tiger's master's ultimate move qualifies due to its obscene killing power. When his master pulled the attack and didn't even make physical contact with Tiger, it still left severe bruising and caused Blood from the Mouth.
  • Shows up early in The Fast and the Furious (2001): Brian, in his first drag race, uses his nitrous too early and is in danger of losing the race. In desperation, he uses a second nitrous burst, still loses, and severely damages his engine as a result. No one in the entire series of movies ever uses nitrous twice, except for this one instance.
  • Ghostbusters: The Proton Packs fire a stream which can snag a ghost like a lasso. But the device is very unstable, and if the proton streams met, it would cause a "total protonic reversal", leading to all life coming to an end simultaneously and every molecule in the user's body to explode at the speed of light. They're forced to use it to end Gozer's threat at the end of the first movie. Thankfully, all it does is cause a big boom and cover New York in marshmallow, because seemingly all the effects remained on the other side of the portal.
  • Marvel Cinematic Universe: Some of Ant-Man's more elaborate abilities are treated this way:
    • In Ant-Man, going beyond subatomic size can only be accomplished by disabling the suit's regulator, which means you aren't coming back once you do. Scott finds a way to do it, though, albeit requiring a specific setup.
    • Captain America: Civil War: Scott turning to giant size.
      Ant-Man: On my signal, run like hell. And if I tear myself in half, don't come back for me.
      Captain America: You sure about this, Scott?
      Ant-Man: I do it all the time! I mean, once. In a lab. And I passed out.
    • Ant-Man and the Wasp exploits and explains both of the above: safe "bridges" to the subatomic world only appear once in a century, and Hank Pym has to develop a whole new machine to properly shrink (and later return) in a ship so he can go there in search for his disappeared wife; and the taller you grow, the least you can keep yourself conscious, given the human body will pass out due to the extra weight and increased oxygen intake.
  • In Shall We Dance 1996 and 2004, this trope is applied to a dangerous maneuver in ballroom dancing.
  • In Overdrawn at the Memory Bank, Apollonia watches a film on Identicube/Computer Interfacing when it becomes clear that they need to save Aram Fingle when his body is misplaced. It's this trope as it is highly possible that both the person in the Identicube and the person connected to the computer could end up losing their minds, becoming vegetables.

  • Death magic in Lois McMaster Bujold's The Curse of Chalion causes both the target and the caster to die as their souls are borne off to the Bastard's Hell (when it works at all). Luckily for some so affected, not only is the Bastard's Hell more of A Hell of a Time than a Fire and Brimstone Hell, but they don't always stay there, as some of the other gods may take them up. This also means while unsuccessful attempts or research are regarded as attempted murder (at least) and dealt with by temporal authorities as such, successful attempts are not prosecutable — not only because there's nobody left to prosecute, but also because if it works, it's considered divine intervention.
  • German author Hans-Hellmut Kirsch, in one of his "Gunner Asch" novels set in WW 2, 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 breech 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.
  • Robert Jordan's The Wheel of Time:
    • The use of "balefire" is forbidden by the magic users of the world, and when people use it anyway, they're exceedingly careful with it. Balefire doesn't just obliterate its target, it goes back in time to do so, with all the potential paradoxes that implies. Entire cities and their recent histories disappeared from the face of the earth before the mages, good and evil, decided that maybe gratuitous use of balefire wasn't such a good idea. When Rand begins using it for more than a minute, it is seen as a sign of his rapidly deteriorating mental state impacting his judgment, though he is technically correct that balefire is the only way to ensure enemies such as the Forsaken are not resurrected by the Dark One.
      • In the last book of the series, so much Balefire has been used the world itself starts falling apart, with cracks in the ground leading to nothingness.
    • Picking apart a weave of the One Power rather than leaving it to dissipate is a Dangerous Forbidden Technique among the Aes Sedai, and just a bloody dangerous technique among the Aiel Wise Ones. If executed perfectly, it won't leave a telltale "residue", which normally lets one channeler see exactly what another has done, but failure is extremely easy and can produce a range of consequences, including a lasting "fallout" effect that makes it difficult to cast spells in the entire region for a year or more. When Elayne tries and fails, it produces a burst of wind. A burst of wind with the force of a small nuclear explosion.
  • Mercedes Lackey's Heralds of Valdemar has the "Final Strike", in which a mage uses up all his energy in an offensive spell, thus killing himself along with whatever is aimed at. It works, too, in the tragic ending of the Last Herald Mage trilogy. Elsewhere in Valdemar, Vanyel's already massive power results in a Final Strike that is so literally earth-shaking that the geography of northern Valdemar is forever altered, and in the Owl Knight trilogy poor old almost-powerless Wizard Justyn must expend his Final Strike to destroy the single bridge that stands between a marauding barbarian tribe and his fleeing village.
  • From the Harry Potter series:
    • A set of three spells is known as the "Unforgivable Curses"; their use lands an automatic life sentence in Azkaban. This is mostly due to their power; one brainwashes, one tortures, and one just kills. It's almost impossible to use them without really, truly wanting the consequences, meaning that their use proves the user's malice.
    • The use of 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.
    • The drinking of unicorn's blood grants one life, even when one is all but dead, but at a terrible cost: that one lives a half-life, a cursed life, from the moment the blood touches their lips.
    • Fiendfyre is an incredibly powerful fire spell capable of destroying even Horcruxes, but it is also extremely difficult to control. When Crabbe used it against Harry and his friends, the only person he killed with it was himself and the soul fragment in the Horcrux.
  • The Pendragon Adventure: It turns out that all Travelers can warp reality like Saint Dane can, but doing so drains the life force of Solara. Saint Dane avoids these drawbacks by relying on a warped version of Solara based on darkness.
  • In Anthony Reynolds's Warhammer 40,000 novel Dark Apostle, creative thinking is viewed like this by the Mechanicus. Dangerous enough to be sealed away in a separate brain.
  • The Dragaera series has "Elder Sorcery", which involves the direct manipulation of raw chaos, and the practice of which is a capital crime by imperial edict. Those who research and practice it do so mainly out of curiosity or the search for knowledge, since elder sorcery has long since been supplanted by the much safer and easier use "normal" sorcery, where the energy of raw chaos is first filtered through the Imperial Orb before being used. However, there are some circumstances where normal sorcery doesn't work, forcing the characters to resort to elder sorcery.
  • In The Magician's Nephew, the Prequel to The Lion, the Witch, and the Wardrobe, there is a dark spell called the Deplorable Word. When it is spoken, every form of life in the world with the sole exception of the speaker is killed instantly. Jadis boasts about the extensive measures she took to learn this and then use it to kill everybody in her homeworld as part of her backstory. Considering the time Lewis wrote it, it's quite blatant what it's supposed to symbolize.
  • The Dresden Files:
    • A wizard's death curse. Put simply, the wizard, knowing they are about to die, draws up all their power and unleashes it in an extremely powerful spell, usually a curse on whoever was killing them. This leaves no energy to keep the brain or heart working, so the wizard dies immediately on casting.
    • Hellfire, which is demonic power that enhances spells but only available when your soul is corrupted by a Fallen Angel. Soulfire, Hellfire's divine counterpart, uses the stuff that comprises your soul as the power source. Use too much Soulfire without giving yourself time to recover and your soul literally evaporates into your spells, killing you (and maybe then some). It's not so much forbidden as simply not available to most people have access to, however.
    • Any sort of Black Magic qualifies for human wizards and practitioners, as every time you break one of the Seven Laws, you corrupt your own psyche enough that breaking them again seems easier and easier to justify. Prolonged usage can progressively turn even the best-intentioned Black Magic user into a gibbering psycho. Plus, the White Council is very likely to cut your head off if they find out what you've done - it's their experience that not turning into a mass-murdering Big Bad after you perform one of these seven acts is rare enough to make getting out the ax before you can get started their first resort. The Council has one enforcer, known as the Blackstaff, whose namesake weapon insulates his mind from the effects and is thus free to perform any magic he sees fit in the line of duty.
    • Casting spells inside a ring of fire, is forbidden for anyone affiliated with the White Council who is not a Warden. Doing so isn't considered black magic, but it amplifies the power of any spell cast to dangerous levels, as well as the effects of any mistakes made during the casting, making doing so extremely dangerous.
  • In Garth Nix's Old Kingdom series, the last of the bells of the necromancer throws everyone that hears it deep into Death, including whoever rings it. There is nevertheless a point in the series where the situation is desperate enough for this to seem like a good idea.
  • In Perdido Street Station, Isaac relates to Yagharek how a previous administration's Torque experiments were banned once pictures of what that utterly-malignant energy had done to a rival city went public.
  • In Pact, summoning a demon is actually spectacularly easy — all you need to do is state their name a certain number of times, and they will come. Of course, there's nothing preventing said demon from immediately inflicting a Fate Worse than Death upon you if you don't take extensive precautions, and even if you are protected, a demon is defined by its pure hatred for existence itself, and summoning one will diminish the world as a whole—candles get a little less bright, gasoline lasts a little less long, and people are a little bit worse to one another. There's no known way of reclaiming what the demons have already taken from the world. In some cases, there's no way of knowing what was taken.
  • Jin Yong, who writes Wuxia novels, loves this trope, but none are more (in)famous than the Sunflower Manual/Bixie Swordplay Technique (featured in The Smiling, Proud Warrior), which requires its male adherents to castrate themselves and slowly makes the practitioner more and more feminized.
  • In the Schooled in Magic series, those who perform the necromantic ritual on another person receive vast power which corrupts their mind and destroys their humanity. It is a temptation for many who desire the power, but it is strictly forbidden by all and for all. In this series, fully 2/3rds of the known world is controlled by insane necromancers who the rest of the world is at war with.
  • In Poul Anderson's "The Sensitive Man", the main character's abilities, which lead many to speculate that he's an alien, a mutant, or genetically engineered, prove to be Charles Atlas Superpower in the end. He explains how many are found in humans — mostly psychotics — and he's learned to draw on them. And since there are good reasons why normal humans can't normally do them, he's about to have a nervous breakdown because of the prolonged usage.
  • Journey to Chaos: Videlct Mens greatly amplifies the might of warriors and mages but overuse of it can kill them or drive them insane. This is why Tiza has to obey a number of rules set by mentor when using it. They boil down to "Don't use it unless you've passed the Godzilla Threshold".
  • In Fate/Zero, Kiritsugu Emiya can use the 'Innate Time Control' magecraft to internally affect time - speed it up for superhuman reaction time in combat, or slow down his bodily functions to avoid a search-and-destroy system. Bad thing, once Kiritsugu stops using it and his body automatically re-synch with the rest of the world, he can suffer very ugly internal injuries.
  • In Larry Correia's The Grimnoir Chronicles, Actives who draw hard enough on their power die. Most who do during the course of the trilogy were already mortally wounded. None of them survive.
  • Although not illegal, a gunsmith in Stephen Hunt's The Court Of The Air warns Oliver that multi-shot firearms are called "suicide guns" for good reason in their world: bullets are made of glass and explosive tree sap, not metal and gunpowder, so loading more than one round at a time poses a very high risk that the shock wave from your first shot will rupture your second bullet's sap-chambers and make the weapon blow up in your hands. In the concluding battle, the Court wolftakers reveal that they've licked this problem by cushioning individual cartridges against such shocks and thus, developed glass-bullet machine guns fed by rubber ammo-belts.
  • Overexert your magic in the world of Rivers of London, and you're liable to give yourself a stroke or cerebral aneurysm. Some specific magical effects also have direct harmful effects, such as the face-warping spell that Punch uses on his possession-victims that made Lesley's face fall off when it lapsed.
  • Cradle Series: The Blackflame Path, a sacred art stolen from dragons, which was used to build an empire. In a world where Asskicking Equals Authority and everyone challenges everyone, no one challenges the Blackflame sacred artists. Not only is it focused on offense to an insane degree, but the flames are not designed for humans; they slowly eat away at mind and body, resulting in the imperial family slowly dying out without any outside intervention at all. When Eithan admits that he plans to train Lindon in this path, Cassias starts screaming.
  • Shapeshifting into another person in The Licanius Trilogy is excruciatingly painful and difficult. It also requires that you personally kill the individual you plan to impersonate.

    Live-Action TV 
  • Juken Sentai Gekiranger features the Ju-Ju-Zenshin-Hen, which allows the user to take on a super-powerful beast-like form. The bad news: transformation is permanent. The worse news: if your technique isn't perfect, your life's gonna suuuuuuck. A Wolf Fist user winds up transforming into an out-of-control werewolf periodically, but at least he gets restored into his human form. The Fly Fist user (no, really) isn't so lucky, winding up an anthropomorphic fly who is about the size of a mouse. He ends up getting swallowed by an evil Chameleon Fist user and is resurrected along with her after she dies...
  • Mahou Sentai Magiranger also has one. Anyone who uses Chronogel's forbidden time spell will die via getting sucked into a wormhole that appears on their chest while it sucks other things like matter and time into it. This curse was deliberately placed on it - apparently, the use of time magic is so dangerous that making sure the universe is screwed if you use it is the best way to protect it. Yeeeah.
  • Used on the main character in Eli Stone. When Eli needs to see the future with more clarity, he asks his acupuncturist Dr. Chen to use a little-known needle combination known as "The Dark Truth." After doing it once, Eli nearly has a heart attack, which makes Chen swear it off. So Eli winds up going to Chen's Distaff Counterpart and rival. He actually has the procedure done at least three times, which is probably why his aneurysm gets worse by the end of Season 2.
  • L's fiddling with the Death Note rules in the live-action movies could be considered this. There's also the more common in the anime world "technique" of Shinigami intentionally lengthening lives at the cost of their own.
  • In Supernatural, Sam's demon blood-drinking to power psychic abilities takes a toll on his sanity and turns him into an out-of-control addict. It gets worse when it's revealed all he did was just so he'd be tricked into releasing Lucifer. Since then, he went cold turkey (...with some exceptions...). In order to finish the Self-Sacrifice Scheme to let Lucifer possess him so he can jump into Lucifer's prison and prevent the world from being razed, Castiel says this requires for him to drink A LOT of blood. Castiel also hints that Lucifer's current Meat Suit has to drink gallons of demon blood just to keep him in.
  • The Kamen Rider franchise has many modes that are dangerous to the user. Whether or not it lives up to the danger varies, from "one use kills major characters" down to "I Thought It Was Forbidden but he uses it just fine over and over." In order:
    • Kamen Rider Stronger: Yes, it's Older Than They Think: long before form changing became the norm, the first Rider to do it has Charge Up, generated by a device implanted Shigeru's body. If he doesn't disperse the extra power in one minute, it will explode, blowing him to very small smithereens. Needless to say, he's never failed to finish the fight and execute his Finishing Move within the time limit. Meanwhile, Tackle has the powerful Ultra Cyclone attack. Using it while already dying from poison finished her off.
    • Kamen Rider 555: The Rider Gears run on Orphenoch DNA. The members of the Ryusei School were experimented on, the villains attempting to make new Orphenochs, so they can all activate it, but full compatibility isn't guaranteed. The Kaixa Gear's side effect: enjoy turning to dust once you de-transform or after a certain amount of time has passed. One use, you die, period. The Delta Gear's side effect is addiction, making you go Ax-Crazy in pursuit of getting to use it again at any cost. In both cases, morphing at all is the forbidden technique until they finally find their way into the hands of their main, compatible users. (Even then, using the Kaixa Gear starts to take a little more out of a Kusaka every time, with characters warning him not to use it.)
    • Kamen Rider Blade: King Form causes Kazuma to pass out the first few times he uses it. However, even once he gets the hang of it, the problem is that it slowly turns you into an Undead, one of the monsters of the series.
    • Kamen Rider Kiva: The Dark Kiva armor is typically used by the Big Bad and would prove lethal to any human who tries. A major character has no choice to use it to battle his even-stronger monster form, at the cost of his life.
    • Kamen Rider Double: Twin Maximum, in which Double activates two Maximum Drives at the same time, temporarily taking his power up to 200%. Each of his battle modes is powered by two Gaia Memories. You activate the Finishing Move by placing one of them in that mode's weapon (for weapon finishers) or the side slot on the belt (for physical finishers.) Doing both at once is NOT recommended, as demonstrated when Shotaro impulsively uses it in one battle, which lights him on fire and severely injures him. In the final battle of the series, Double's Super Mode is powerful enough that he can combine the Xtreme and Prism Memories' Maximum Drives without ill effect. Also, the Fang Memory drives the user dangerously feral, but Philip was able to get control of it in one episode.
    • Kamen Rider OOO: This time, the suit changes in thirds! Three of a kind gets you a Set Bonus, but side effects may include injury and insanity. The Super Mode comes with an even bigger risk: much like Blade King, OOO Putotyra takes the user one step closer to becoming more like the monsters whose essence powers it. Also, its first few uses make it so uncontrollable that Eiji has lost the ability to tell friend from foe and attacked his teammates. Unfortunately, it has the tendency to activate on its own...
    • Kamen Rider Gaim: A character who has made a Face–Heel Turn and gone off the deep end is given a Super Mode capable of keeping up with that of the hero. The problem is, it drains the life of the user, and the inventor told him point blank that using it would probably kill him. (In practice, its power level turns out to be as advertised, but whenever it sucks more energy from the user, the user is wracked with enough pain to barely able to stand, let alone fight. If not for the fact that the hero didn't want to harm him, using it would probably get him killed by an opponent, even a weaker one, before the life drain became fatal.) Oh, and the hero's super mode makes him more like the monsters, but this doesn't seem to come with any lack of control or turning into a monster like in OOO.
    • Kamen Rider Ex-Aid: If you haven't had the compatibility surgery, trying use a Gamer Driver at all will wreak havoc on your body. Meanwhile, Proto Gashats (basically, the Super Prototype of the Transformation Trinket, comes with powers the main ones don't have) harm the user a little more each time; "fortunately," the Big Bad creates a Super Mode that lacks the side effect and heals him from his past uses of his normal mode. Also, Drago Knight Hunter Z is an emergency weapon for when the risk of going berserk is not as bad as whatever is already going on. However, the secret to controlling it is that it's based on a four-player co-op game; each of the Riders is supposed to wear part of the armor.
    • Kamen Rider Build: The Blizzard Knuckle amps up your attacks with ice power. It can be used to transform, if you don't mind dying. Also, there's an upgrade that can be applied to any hero or villain using the Hazard Trigger that increases your strength at the cost of dying if you are defeated in your new form. Major characters have been lost to both of these. Speaking of the Hazard Trigger, its "makes the user go insane" factor is no joke. It takes full control of Sento and drives him to kill with its first use. The other insanity-inducing power-ups, including this very series' Sclash Driver, are something that never drives the user as nuts as originally expected and is controllable in the end, but Hazard will turn you into a merciless killer and remains a weapon of last resort for a long time. (Eventually, new armor that can control it is created.)
    • Kamen Rider Zi-O: The good news: Geiz Revive is a supermode supposedly able to handle anything up to and including Zi-O's evil future self, the dreaded Oma Zi-O. The bad news: it warps time and space to counter Zi-O's own space-time abilities, and the human body cannot long withstand being at the epicenter of that. If he uses it too often, it will endanger his life. At one point, another character was able to successfully stop him by taking a Curb-Stomp Battle from Geiz Revive... which left Geiz unable to fight for some time.
  • L.A. Law has a sexual technique known as "The Venus Butterfly". An accused bigamist says that it is his key to success with women who would otherwise be out of his league and teaches it to his lawyer very reluctantly as he has always believed it had the potential to sexually enslave women.
  • The bonehead maneuver in Babylon 5: Opening a jump gate within an existing jump gate, resulting in a massive explosion of energy that the ship who triggered it is highly unlikely to survive or outrun. The heroes only use it because it was the only way they could think of to shake the Shadow ship trying to kill them. Doubly dangerous, as this destroys the jump gate, leaving the system inaccessible to non-jump drive equipped ships until a (very rare) construction ship drops by to rebuilt the jump gate. On this occasions the planet was already deserted, and the heroes had to additional motive of rendering it inaccessible to grave robbers.
    • Sometimes, a deathbed scan is the only way to get critical information. However, telepaths don't like doing them since many describe the experience as having part of them go with the departed. Those that have done four or five are described as being dead inside. Bester has gone on record doing eight.
  • Resurrection spells in Buffy the Vampire Slayer. They either turn the dead person into a zombie, or make them come back wrong and all screwed up.
    • And of course, the enjoining spell that the Scoobies use to defeat Adam. Giles' knowledge, Willow's magical strength, and Xander's heart, all combined with Buffy's super strength and resilience into one nigh-invincible Slayer, complete with Voice of the Legion and Golden Eyes Of Doom? Cool. Being stalked and almost killed by the First Slayer in your dreams afterwards because the spell disturbed her spirit? Less cool.
  • One episode of Angel reveals that if a vampire has their heart surgically removed, they're unkillable for a certain amount of time but eventually die. The episode focused on a vampire Driven to Suicide after Angel killed his girlfriend, who got the surgery in the hope of taking Angel with him.
  • In Game of Thrones:
    • In a rather borderline case, Stannis uses this via Melisandre's shadow assassin which consumes his own energy. After using it, Stannis is noticeably aged and Melisandre refuses to do it again because it could kill him.
    • Daenerys, lets Mirri Maz Duur cast a dangerous spell to keep Khal Drogo alive. It goes horribly right.
    • We learn why exactly warging in humans is strictly forbidden among the wildlings. There is a reason why Hodor can only speak 'Hodor'...
    • There is an experimental treatment for the fatal skin disease greyscale that has been forbidden for the risk it carries both for the maester administering it (since one slip up could get themselves infected) and the patient (since the cure is basically being skinned alive).
  • In Merlin, using the Cup of Life to become immortal. The result is that the person who drinks from it becomes the living dead of a sort, not a zombie, but tainted still.
    • On a lesser example, magic could be used as part of a ritual to save someone who was mortally wounded, or even allow a barren woman to conceive a child, but this required another life to be sacrificed to sustain the life that was being saved.
  • Several times in the Star Trek franchise, people bring up the dangers of jumping to warp inside a solar system — and somebody does so anyway, usually as a sign that they've reached the Godzilla Threshold. This gets undermined, however, by all the times a starship does just that — sometimes while still inside a planet's gravity well — and nobody makes a big deal of it.
    • Subverted in the Star Trek: The Original Series episode "The Enterprise Incident", where Spock appears to kill Kirk using a powerful Vulcan technique called the "Vulcan Death Grip". In reality, this was part of a plan devised by Kirk, Spock, and Bones to infiltrate the Romulan ship, which involved Spock becoming a Fake Defector; Spock actually only used a more intense version of the more familiar Vulcan Nerve Pinch to render Kirk unconscious and make his vital signs undetectable, claiming he had killed him to win the Commander's respect. There was actually no such thing as a "Vulcan Death Grip". (They were counting on the Commander to not know that, as Kirk later told Nurse Chapel.)
    • The Star Trek: The Next Generation 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. 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.
    • There's also warp speed saucer separation. This is because the moment the saucer leaves the stardrive it immediately starts losing speed. If they don't pull the stardrive away in time, they would crash.
  • Once Upon a Time has a couple:
    • The Dark Curse (the spell which kicks off the events of the series) is one of only a few reliable ways of traveling between worlds. However, even most of the villains in the Enchanted Forest are too afraid to use it since activating it requires killing the person you love the most. Regina's desire for revenge on Snow White pushes her to the point of using the spell in the flashbacks of the first couple episodes. This is something of a variant because, rather than being dangerous for the user, it's dangerous for those around them; however, it may still count as Maleficent implies that the actions necessarily will result in permanent psychological damage.
    • There's also 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 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.
  • Stinger of Uchu Sentai Kyuranger uses one that involves poisoning himself before he fights his brother in Space 20. It heightens his fighting abilities, but also endangers him. Worse, his brother turns him against other Kyurangers.
  • In Power Rangers, morphing without a Power Coin is considered this. When Kat steals Kimberly's Crane Power Coin, Kim is forced to morph using the energies of the other Rangers until they're able to get the Power Coin back, causing drain to the entire team, Kimberly the most. Later, Adam ran the risk of killing himself when he morphed using the damaged Mastodon coin, though Sentinel Knight fixed this later on.
  • Parodied in The Suite Life of Zack and Cody. A secret technique in Croquet that allows one to go through every single loop, but carries a substantial chance of shattering ones' bones. No such technique does or could exist since it would require the ball to do multiple 180 degrees turns.

    Pro Wrestling 
  • A fair few wrestling moves involve both the opponent and/or the wrestler themselves landing on the ground, with the victim of a given move sometimes landing on their head; Suffice it to say that even accounting for Kayfabe, wrestling is extremely dangerous.
  • Some moves can cause lasting damage to the performer's body. The two most glaring examples are the moonsault and the tombstone piledriver, both of which involve landing full force on the knees. The repeated stress of the latter move is why Kane switched finishers to the chokeslam and why The Undertaker developed the Last Ride.
    • Speaking of the piledriver, an actual piledriver (not the tombstone version that the Brothers of Destruction use - that variant is ironically a lot safer to perform and receive) is something that WWE superstars haven't been allowed to use for over a decade due to Owen Hart using the move on "Stone Cold" Steve Austin, giving him the neck injury that would eventually end his career (no offense to Owen). Come 2013, the fact that CM Punk used it at all, let alone on John Cena (who's had a history of neck problems), upped the "Holy Shit!" Quotient of the match they were in. Said match is now considered one of the best TV matches in RAW history.
      • Speaking of the piledriver some more, there's an even more devastating variation of it known as Kudo Driver, the Vertebreaker to you WWE fans, considered one of the most dangerous moves in all of wrestling. It's like a piledriver except, instead of holding your opponent upside-down in front of you by their torso, you hold them upside-down behind you by their arms, with the two of you back-to-back. This means their arms are restrained and there's no way to use your legs to cushion the impact. Garbage Wrestler promotion FMW's second biggest star Megumi Kudo invented it, where it was still one of the tamer ways to end a match there. Unsurprisingly, WWE banned it in 2003, but it's still used by wrestlers in other, more reckless promotions, such as by Mariposa on Lucha Underground.
    • Hulk Hogan with the Legdrop and "Stone Cold" Steve Austin with the Stone Cold Stunner. Landing directly on your ass hundreds of times a year must be great for the spine and neck (yup, they're connected).
  • Most aerial techniques, but the 450 Splash and the Shooting Star Press are really bad; not only do they wear your body down over time, but messing up could seriously hurt you on the spot. Just ask Brock Lesnar.
    • Booker T's Harlem Hangover (a top-rope flipping Guillotine Legdrop) combined the wear and tear of aerial moves and legdrops. Back problems caused him to abandon the move after only a few years of use.
  • The diving headbutt, and German Suplex (which puts a lot of pressure on the spine), especially nasty since they were both signature moves of Chris Benoit and may have caused the brain damage that resulted in the deaths of himself and his family.
  • Technical wrestlers generally avoid this as most submissions don't actually put that much pressure on the body. That said, WWE has discouraged many holds which involve the user bridging on their neck, often making mat segments less impressive than those of the other majors.
  • Certain moves can get banned as part of a wrestling angle, usually by a heel authority figure.
    • banning the piledriver and its many derivatives is a stock plot in professional wrestling, especially in Memphis during the territorial era and Mexico City even after the territories fell. In fact the banning of the move is why there are so many derivatives of it, though just as common is the heel simply sneaking the move behind the referee's back (Paul Orndorff was especially notorious for doing it, Ricky Morton the most famous victim).
    • At the 2007 Survivor Series, Shawn Michaels and Randy Orton faced each other in a title match where Michaels would get disqualified if he used his finisher, the Sweet Chin Music. To even up the odds, however, Orton's championship would go to Michaels if he got himself intentionally disqualified or counted out. Orton won the match due to Michaels getting distracted trying to use the move but stopping himself, but then used it on him after the match was over.
    • In 2008, Vickie Guerrero banned The Undertaker's then-recently-added submission move Hell's Gate. Her reasoning was due to it causing superstars to get injured and cough up blood. She would strip Undertaker of his World Heavyweight Championship for creating it in the first place, and the ban wouldn't get lifted until over a year later by Teddy Long.
    • In 2011, Vickie would strike once again, this time banning Edge's spear briefly, and firing him for using it. One week later, Teddy Long once again lifted the ban and reinstated Edge.
    • In 2012, after Sheamus accidentally hit Ricardo Rodriguez with a brogue kick instead of intended target Alberto Del Rio, Del Rio and David Otunga tried to push general manager Booker T to ban the move. Booker briefly banned it while investigating whether or not to ban it permanently, but shortly after pointed out that they should understand the risks involved in pro wrestling, and lifted the ban on the move.
  • The Burning Hammernote  is considered to be flat-out the most dangerous move in all of Professional Wrestling. The innovator of the move, Kenta Kobashi, has only used the move seven times in his entire career, and every single time it has put away the opponent for good. This fact just added to the "Holy Shit!" Quotient during the WWE Cruiserweight Classic where Brian Kendrick, a veteran who was doing anything he could to stay in the tournament, used the move against Kota Ibushi in a last ditch effort to beat him. And even then, it wasn't enough to put Ibushi away.
  • On that note, the Ganso Bomb, essentially a marriage between a powerbomb and a piledriver wherein the opponent is dropped right on their own neck. It's about as dangerous as the Burning Hammer, perhaps even more so. For decades Mitsuharu Misawa and Toshiaki Kawada were the only two wrestlers willing to do it and even then only did it once in an era where All Japan Pro Wrestling was otherwise all about Serial Escalation.
    • This is because the first Ganso Bomb was, in fact, an accident. Around eight minutes into Misawa and Kawada's January 1999 title match, Kawada delivered a spinning backfist to the back of Misawa's head with such force that he broke his right forearm and wrist. While Kawada continued to wrestle for fifteen minutes (he was booked to win the match, but he vacated the title the next night due to the injury), he was unable to lift Misawa all the way for a powerbomb, and the ganso bomb was an improvised solution.
  • 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. Yoshi Tatsu botched receiving it and ended up with a broken neck, but AJ Styles has grown attentive and actually saved James Ellsworth from injury by noticing he tucked his chinnote  and landing on his hands.

    Puppet Shows 
  • Pili Fantasy: War of Dragons: Learning the Tenth Bodhisattva Seal causes the practitioner to die seven days later as their internal organs are crushed within. This is incredibly inconvenient (aside from the obvious reasons) because it is the only way to save someone from the delayed death effects of the Illusory Fist attack. And a meat shield who will die is needed in front of the person they intend to save, at that.


  • The barra vasca style of javelin throwing. Originally stemming from a Basque martial art, it is basically throwing the javelin as if it was a discus. The barra vasca is an immensely effective style, and a new world record was immediately made. The Finnish javelineers got enthused about this style and pushed it Up to Eleven by soaking their throwing hands in soapy water, inventing the "soap style" with which the javelin flew well over 95 m. Needless to say, the accuracy of barra vasca style is appalling, and only some 10% of the throws ever got in the sector — some throws even landing in the grandstand, endangering the spectators. The style was explicitly prohibited beginning with the Melbourne Olympics in 1956.
  • Amusingly, many then standard pro wrestling moves such as any an all elbow strikes, headbutts and kneeing the heads of downed opponents were quickly outlawed in Shooto's formative years. There was an ongoing debate regarding punching the back of the head for fourteen years before it was officially banned too. In the wider mixed martial arts community branching out from Shooto, the debate is over whether to ban ankle locks or not. The fact that applying an ankle lock is a good way to be put in one is the only reason why debates exist.
  • Fans of Japanese MMA are often surprised to learn soccer kicks, among the most effective and reliable fight ending tactics, are banned almost everywhere outside of Japan.
  • Within elite gymnastics, there are a number of moves which are banned.
    • On floor excercise, all roll-out somersaultsnote  are banned. These skills were banned for women in the 1980s after Russian star gymnast Elena Mukhina was paralyzed attempting one such skill; the 2017 code of points also banned these skills for men.
    • On women's uneven bars, all skills that involve standing on the bars, which were at one time relatively common, are now banned. Notable skills in this category include the Korbut Flipnote , the Layout Backwards dismountnote , and the Mukhina Saltonote . The reason for banning these skills appears to be partly for aesthetic reasons note  and partly because of safety concerns.
    • In 1988, Julissa Gomez was performing a Yurchenko vault (a vault with a round-off entry) when her foot missed the springboard, which pulled her body downwards so that instead of going over the vaulting horse, she crashed headfirst into it, breaking her neck and leaving her paralyzed (she would die a few years later of complications from the injury). Following her accident, the international gymnastics board ruled that a "safety collar" mat must be placed around the springboard for any vault with a roundoff entry to prevent exactly this potential mishapnote . If a roundoff entry vault is performed without the safety collar, it's an automatic zero. An unusual example in that they didn't fully ban the skill, but rather banned a particularly unsafe way of doing it. (Other changes to the equipment were also introduced.)
    • Also in women's gymnastics, the Produnova, known as the vault of death, has a reputation for its high risk of injury. Unfortunately, because of its high value, some gymnasts will attempt it even if they know they can't get it around, which means they have a much smaller margin of error to avoid a catastrophic landing should something go wrong. Rather than ban the skill itself, the governing body decided to effectively ban the unsafe landing specifically — as of the 2017 Code of Points, if the gymnast "lands on the feet [and] any other body part simultaneously", she only gets credit for a single front tuck (almost two and a half points lower in difficulty) in addition to getting the execution deductions for a fall, which makes it not worth doing the skill at all. This way, a gymnast who can actually land the skill consistently will still be able to do it, but a gymnast who can't won't put themselves in danger trying to do it anyway.
      • 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. 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, or even seriously trained), but 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 campnote  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. That pretty much precluded anyone else from trying it, at least until Karolyi retired following the 2016 Olympics (much to Maroney's disappointment, since she wanted to be the first to compete it internationally on the women's side).note 
  • Figure Skating:
    • The Backflip is a well-known example of a banned element within the sport, being outlawed in 1976 shortly after Terry Kubicka became the first and only skater to legally land the trick in competition. The trick's notoriety is largely thanks to Surya Bonaly, who after dropping out of medal contention at the 1998 Olympics, performed a backflip and landed on one foot as a crowd-pleaser, penalty be damned. The Backflip overall is a bit of an unusual example of this trope, as it isn't especially dangerous and it remains a staple of exhibition shows to this day; most likely it was banned for being a highly atypical type of jump that also isn't exactly elegant to pull off in the middle of a routine.
    • In Pair Skating, all lifts must be hand-to-hand, arm, body, or upper leg. This subsequently outlaws a range of dangerous lifts, such as those that involve the Lady balancing precariously on the Man's head, shoulders or back, as well as 'Headbangers' that involve swinging the Lady so that her head passes uncomfortably close to the ice. Like Backflips, these elements remain common sights at exhibition shows, but their risks keep them out of competitions.

    Tabletop Games 
  • Dungeons & Dragons:
    • There exist two magic staffs in the game, the staff of power and the artifact staff of the magi which, while very powerful items in themselves, can be broken for a "retributive strike" which releases every spell inside the staff at once, centered on the caster. Given that the Squishy Wizard is the norm, anyone attempting this strategy had better hope that the 50% chance of getting sent to another dimension comes up.
    • There also exists an incredibly powerful dispel spell called Mordenkainen's Disjunction, which can destroy just about any magic effect, even those created by gods. If it is used for this purpose, however, the caster may permanently lose all his magic abilities and/or anger the effect's creator. And he is no slouch, believe us.
    • Complete Arcane has a 9th-level wu jen spell called Transcend Mortality, which you're not supposed to use except in desperation. It basically makes the caster Nigh-Invulnerable (and its casting is an immediate action, meaning it can be invoked right before an attack hits) and last for about one combat. However, once it expires, the caster instantly die and is disintegrated.
    • This is the point of the corrupt spells in the Book of Vile Darkness (and their Exalted Deeds counterparts, sanctified spells). They are notably more powerful than other spells of their level — for instance, run-of-the-mill Blindness is a second-level spell, while Seething Eyebane, a corrupt first-level spell, causes the target's eyes to spew acid and explode — but there is always a tax, sometimes permanent, on one or more ability scores. The most powerful of these spells is harmful even to prepare and has a very good chance of rendering the caster dead and/or permanently insane (if he wasn't already).
    • Something else mentioned in the Book of Vile Darkness is the Artifact of Doom called the Death Rock. Artifacts are always dangerous, but this one is worse than most; its history does say that its owners tend to obtain great power and are able to conquer empires, but tend to lose the power at the worst possible time, and are usually overthrown in violent insurrections by their enemies. Here's how the Rock works: It gives the user incredible dark powers of necromancy, giving him the potential to raise vast undead armies. But it has a terrible cost; once a week, it demands the user slay his closest friend or loved one, and claim him or her as a zombie slave. If he is unwilling or unable to do so, the Rock and all powers associated with it vanish. Clearly, all former users never realize that if you are willing to do this, you're going to run out of friends and loved ones very quickly (a lot of them will likely stop being your friends before you can use them as the required sacrifices) and be unable to make any new ones; on the other hand, you'll probably make hated enemies very fast...
    • Prior to the 2nd Edition, Orcus was murdered by Kiaransalee, the drow goddess of undeath, who usurped his realm in the Abyss. However, in the Dead Gods module, he Came Back Wrong, becoming an undead demon named Tenebrous, possessing a spell called the Last Word that was so lethal, even gods were afraid to use it. This didn't stop Orcus, however. Despite the fact that it was literally consuming him from within, he used it in his campaign to restore himself to life killing several gods using it in order to reclaim his Wand, and regain his domain in the Abyss. (He succeeding in doing all that, but fortunately, failed in his ultimate goal: becoming a true god.) After gaining back his true form and position, he lost the ability to use it. (The gods have since taken steps to prevent anyone from using it again.)
    • From 3.5 edition's Tome of Battle: Book of Nine Swords, the Shadow Sun Ninja Prestige Class is a class of good-aligned warriors that accept the dark aspect within themselves and not reject it, allowing them to use the power of both sides. The final ability they learn, Balance of Light and Dark, lets their inner darkness run rampant, transforming themselves into a shadow form with a number of special immunities, causes negative energy spells used on them to heal instead of harm them, a bonus to Hide skill checks, and attacks made when in areas of darkness or shadowy illumination. It also grants the Shadow Sun Ninja the option to inflict negative levels with no saves allowed and heal a small amount of damage with every successful unarmed attack they make.note  However, for every negative level the Shadow Sun Ninja inflicts this way, they also take a point of Constitution damage once their transformation ends. Low on Hit Points at the end of the shadow form? A character can drop dead from the sudden HP reduction due to CON lost. But wait, it gets worse. Hit 0 CON? The character doesn't even return back to normal, instead dissipating into an inky dark cloud. That starts a 1 to 4-day random time limit to bring the Shadow Sun Ninja back to life, and only the spell True Resurrection will work. Run out of time and then the Shadow Sun Ninja's body reforms as an NPC vampire, shifts immediately from whatever good alignment they were straight down to a champion of evil, has all of the Prestige Classes abilities, oh and they don't have the normal vampire's vulnerability to sunlight. Once this occurs, slaying the vampire still won't let the Shadow Sun Ninja be returned to life with any spell. The only way to save them at that point, is for their allies travel to the Iron City of Dis located in Hell and free their trapped soul being imprisoned there, which will instantly slay their vampire self if it still exists and restore them to life.
    • The Wish spell in 5e works like one of these; use it to cast any spell of 8th level or lower? No problem. Use it to cast a 9th level spell or to cause any intended effect that the user wishes (and the DM deems appropriate)? This is the tricky bit. After using Wish in the latter way, any spell you cast until a long rest will do an unavoidable d10 of necrotic damage, as well as reducing your Strength stat to 3 for 2d4 days. The real kicker comes with the 33% chance that the player who cast Wish will never be able to cast it ever again, throughout the fullness of that character's existence.
    • Another 5e example: Evocation Wizards can "overcharge" their spells to maximize their effectiveness. Doing so once is harmless. Doing it again does a fair bit of damage, which increases drastically from that point on.
  • In the Dragonlance setting, Wizards of High Sorcery view Primal/Wild Sorcery this way. It was three Sorcerers who, fighting an army of Dragons at the end of the Second Dragon War, caused magical storms that wracked Ansalon. These three Sorcerers ended up becoming the first Wizards after being taught High Sorcery by the gods of magic.
  • Several of the noble families from the Ravenloft supplement Legacy of the Blood possess the knowledge of a Dangerous Forbidden Technique or two, usually in the form of feats that only family members or their elite henchmen can select.
  • In the Mystara setting, Glantrians' use of the Radiance is considered this trope even by the Alphatians, who normally consider even the darkest sorts of magic to be permissible. This isn't because it's dangerous to the wielder (which it is), but because using the power of the Nucleus of the Spheres threatens to drain all magic from the world, bit by bit.
  • Overuse of what should have been a Dangerous Forbidden Technique - defiler magic, powered by the life force of creatures and the natural world - is what made Athas, the planet where Dark Sun is set, into a desolate wasteland.
  • In the Sorcerer game from the Mage: The Ascension line, there is one Path that can have this effect: Cursing, which is Exactly What It Says on the Tin. Specifically, you can create an absolutely vicious curse rather than the normal version. The problem is, though, that it renders the caster a vegetable.
  • Genius: The Transgression has Deep Inspiration, which lets you draw out Mania directly from the Genius's mind, even if the Genius is "empty". Unfortunately, doing so too often or with too much power runs a very real risk of turning you into an Unmada, and if you keep pushing it even after becoming Unmada...It's a bad idea.
  • Changeling: The Lost features Goblin Contracts, magical powers that are cheaper to buy than standard Contracts and have nice effects (open all the locks on a building, see the future, drain an enemy of all their Glamour). The catch? Well, they also have side effects that will likely screw you over (respectively, your locks fail the first time someone tries to break in, you go mad, you lose all your Glamour).
    • One particular Goblin Contract is "Call the Hunt" which has no real catch because it is its own catch; it calls forth a hunting party of True Fae. If the changeling who uses it doesn't run away fast enough, he or she will likely be killed or, even worse, dragged back to Arcadia to be tortured once again.
  • Demon: The Descent features a technique called "Going Loud". In simple terms this transforms your character into their demonic form, sets your magic Power Level (called Primum) to 10 (out of a maximum of 10) completely refills your Mana (And having maxed Primum means you are able to hold LOTS of Mana) and allows you access to basically ALL of the magic spells in the game. The catch? Well, the whole point of this game is that Demons need to impersonate a human in order to avoid the attention of the games Big Bad. The human identity they adopt is called their "cover" (in the espionage sense of it being a cover identity). Going Loud irrecoverably destroys that cover, effectively erasing every detail of it from existence, which means that the Big Bad knows exactly where you are...
    • There are also Exploits, incredibly unsubtle delays of power that can do anything from resurrecting the dead to causing rains of fire to kill somebody so hard, it erases their last action from existence. Every one of them requires a Compromise roll, which may not destroy the Cover, but can certainly damage it.
  • Princess: The Hopeful has the Royal Favours power of the Court of Storms. Once per session, the player may declare that the Queen of Storms is manifesting power through their character. This lets her use any Tempesta or unaligned Charm with a rating of half the character's Tempesta or less, with as many successes as the player wants and none of the normal costs. The catch? The character also takes Resistant Lethal damage equal to the number of successes chosen, and the book specifically states that the Queen of Storms has killed her own soldiers in this way.
  • Plenty of Charms in Exalted come with heavy tolls. The more common include pushing up your Limit track, and Abyssals have some that increase resonance or mean that they'll experience Cessation of Existence upon death.
    • The Infernal Exalted get a good number of these, mainly because they're learning Charms that make them more like their Yozi patrons. Learn a Charm that gives you increased authority over lesser demons? That means greater demons are allowed to walk all over you. Learn a Charm that perfectly blocks Social attacks? That's because it turns all noise into wretched discord that makes you want to kill. Learn a Charm that allows you to communicate telepathically? Shame you can now only vocalize laughter for the rest of your days.
  • The Words of Power from GURPS: Thaumatology. Saying one will knock most characters unconscious and the most control you can ever have over a Word is none at all, trying to control it only makes things worse.
  • Scion has the Avatars, which allows Gods to channel the power of a Purview at the apex of cosmic power, so much that anyone who fights them has to become one in order to match. However, while the cost to activate it is rather modest game-wise, there are some major prices to be paid: first, you suffer the strongest Fatebinding upon activation, second, if you die, all the Avatars you learned to channel get loose all at once, and third, you activate it in the domain of a Titan, you'll attract every Titan Avatar in it, and chances are, they'll already have their own powers ready as well. Congrats, you now get to fight five or six beings with the same power as you.
  • Magic: The Gathering:
    • The game has a bunch of cards that are effectively this. You can't miss them, because they all inform you that you lose the game after a certain amount of time or if a certain condition is met. For example, Final Fortune allows the user a free turn at a cost and color that doesn't normally get it, but the user loses the game at the end of that turn if they haven't won yet. Lich and its variants protect you from dying through life loss, but kill you under other circumstances, such as an empty graveyard.
    • For Black, there is no technique dangerous or forbidden enough not to use. In story terms, it is the color that regularly makes use of death magic, bargains with demonic beings for power and paying the price for that power without a second thought; Mechanically, many cards require either a payment of life points or the sacrifice of a creature upfront as payment, or repeated payments over time for upkeep. The logical extreme of this mentality is the "Suicide Black" deck, an aggressive deck that uses cards like Carnophage which are powerful for their mana cost but possess drawbacks that will kill you if you don't win quickly. It's referred to as "tearing your arm off and beating your opponents to death with it before you bleed out".
    • The best definition of this trope is the card Demonic Pact. Each turn, you must apply one of its effects, but you can't use the same one twice. These effects are draining a sizable chunk of someone's life, making an opponent discard 2 cards, draw 2 cards yourself and losing the game.
  • Blue Rose has Sorcery, generally banned in most kingdoms, to the point that legalizing the study of sorcery in Aldis has been greatly controversial. While arcana are generally legal in Aldis, sorcery allows an adept to directly harm, control or invade other individuals, mentally or physically, as well as create undead or summon darkfiends, and are considered crimes against all sentient beings. Trying to classify sorcery is tricky, as few arcana are clearly sorcery, and even those that are can be wielded for a period of time without any real damage to the adept if he is sufficiently resilient. Unfortunately, sooner or later, The Corruption takes hold, and the adept will either fall into the arms of Shadow, die a painful death and become transformed into a walking corpse, or try to cleanse himself even as corruption makes it harder. Many people who use sorcery are scrupulous enough to embrace the corruption that comes with it, but the temptation is always there for any arcanist, even those with the best intentions.
  • The Yu-Gi-Oh! card game has a few perfectly legal cards that could be considered this. One is Destructive Draw. It's a Continuous Trap that lets you draw twice during your Draw Phase if you have no cards in your hand when you start your turn. However, you take 700 points of damage per turn, and unlike most cards like this, it's possible to lose the duel this way. Also, this card is hard to get rid of; doing so causes the player who uses it 3,000 points of damage.
    • At least there are ways to turn that one to your advantage, like Prime Material Dragon. And the even worse card is Lucky Punch. This is also a Continuous Trap, and it lets you toss three coins once per turn when your opponent attacks. Get three heads, and you get to draw three times. (That's only a 12.5% chance, by the way.) Here's the catch: If you get three tails, the card is destroyed, and if it's destroyed in ANY way, you lose 6,000 Life Points. (Because it isn't considered damage or a Life Point payment, there's really no way to avoid it or convert it to Life Point gain.)
  • In Ironclaw Unholy magic (such as Necromancy, offensive Lutarist spells, and a few Druid curses) summons vengeful spirits to do magic for you, there is a chance that these spirits will do other things like animate random corpses, possess people (including the caster), or make scary sounds that freak people out (sometimes to death).
  • Hc Svnt Dracones: Transcendent implants at Cuil 3 or higher generally have a significant chance of causing messy, painful death for their owners, it's guaranteed if someone at Cuil 5 tries to use their implant. Oh, and the Cuil level of an implant temporarily increases each time it's activated in combat.
  • In Warhammer 40,000, any Psychic Power that requires 3 Warp Charges is this. You only harness a Warp Charge on a roll of a 4+, which means that, on average, you'll need to roll two dice for every 1 Warp Charge requirement, and probably significantly more if you MUST have it go off. This means that you will need about 6-9 dice to reliably use a 3 Warp Charge Power. Given that the average army's psykers can maybe get 10 dice to use in total (and that's if you're lucky) this is a significant investment of resources. You also have to declare all the dice you want to use for the attempt before rolling them; if you choose 7 but five came up a dud, the remaining two are wasted. On top of that, if any harnessing attempts result in 2 or more 6's, the Psyker perils and has a chance to be devoured by Daemons (which can result from such pleasantries as being flat out removed as casualty to simply forgetting the spell then taking a punch to the nuts). Worse if you decide for him to roll on one of the Daemonology Disciplines without being the proper faction (Grey Knights for Sanct, Daemons for Malefic); this table perils on any sets of doubles, not just two 6's.
  • In Warhammer, elves taught humans magic using a Dangerous Forbidden Technique that lets the student master one color of magic in a very short period of time (a decade or two), at the cost of it inevitably driving them insane... in two or three hundred years.

  • Nova blasts from BIONICLE, during which the Toa unleash all of their Elemental Powers in a massive explosion. Not only does it leave the Toa with no power left, depending on the type of element it can also easily kill anyone in a close (or even not-so-close) vicinity. As the Toa adhere to a strict Thou Shalt Not Kill code, the idea of a nova blast is unthinkable, and thus it is the ultimate Godzilla Threshold for a Toa. Only two nova blasts were ever initiated throughout the story's length: the first by Gali Nuva sank an entire island, and was only activated as a last resort to defeat a powerful Makuta after the island's evacuation; while the second by Jaller was being charged up as a desperate attempt to buy one of his teammates enough time to undo the Great Spirit's death and consequent collapse of the universe, even if he would incinerate the rest of his team in the process (fortunately, this situation resolved itself before he actually had to release the blast, and he just barely got it under control before releasing it and consequently taking all of Metru Nui with him after his team was teleported there).
  • In the Monster High franchise, Frankie weaponizing her body's electricity by swapping the bolts on her neck is shown to be this, as when she does it on her grandfather's rampaging robot she consequently suffers a Heroic RRoD. She gets better through The Power of Love.

    Video Games 
  • Kingdom Hearts:
    • Channeling the darkness is this for most characters. Riku and Terra pay heavy prices for its uncontrolled usage, getting them both possessed by the Big Bad in the first Kingdom Hearts game and Birth By Sleep, respectively. However, in the sequels, Riku manages to tame the power.
    • In addition, many of the Kingdom Hearts villains themselves cannot control the darkness, with some such as the Tremaine family and Hans paying the ultimate price for using it. Maleficent actually appears to Hades and cautions him not to delve too deep at one point in the story. Ironically, she delves too deep and is slain at the hands of Sora and company (though it should be noted that she had her heart forcibly opened to the darkness by Ansem; she follows her own advice). Hades, while defeated in the Hades Cup, does not die, being a god, and reappears in Kingdom Hearts II not at all worse for wear.
    • The spell Zettaflare shows up. Previously in Bravely Default, it had only ever been used by a final boss being fueled by the power of an evil butterfly. Donald Duck can cast it on a spur of the moment at the cost of knocking himself unconscious for a while. Goofy indicates he's done this before.
  • In the Phantasy Star series, Megid invokes this trope by name. In PS2, it's Cast From Hit Points at a painful rate. In Phantasy Star III it's only invoked in a cutscene, but when it is, it wipes out an entire city in a single casting. Note that PS3's setting is largely medieval compared to the sci-fi ambiance of the rest of the series, so any spell capable of leveling a city is pretty much the equivalent of the Tsar Bomba. In PS4, the negative effects on the player are gone, potentially due to where it comes from and what the stakes are at the time, but it's not easy to access (being guarded by a Sealed Good Is Not Nice in a Can guardian who you need to outwit to get it) and the only other user of the spell is the Eldritch Abomination that threatens to wipe out the entire star system (and, ostensibly, the universe after that) if you fail in your quest.
  • The Chaos Dunk from Barkley, Shut Up and Jam: Gaiden is this for basketball, with the original one wiping out millions of people and getting B-Ball outlawed and is implied to kill Barkley and Balthios when Barkley uses it to kill Shadow Barkley
  • Sonic the Hedgehog:
    • Similar to his anime counterpart, Shadow the Hedgehog can gain an extreme power boost whenever he removes the bracelets from his arms. Unlike the Sonic X version, however, it doesn't appear to drastically drain his energy. He only used this power once in Sonic the Hedgehog (2006) to save himself, Rouge and Omega from Mephiles the Dark, who used two of the Chaos Emeralds to create an army of clones of himself.
    • Although not typically portrayed as such, Super transformations can be this, ESPECIALLY for those who aren't experienced with it. It grants the user invincibility, immeasurable physical and magical enhancement and the power of flight, but it's also tied directly to how many rings the character has on hand. If they burn through their rings, they de-transform and, due to the situations in which the form is typically used, they're pretty much dead. Even when the environment doesn't present an immediate risk, using too much energy at once not only bleeds through the character's stock of rings insanely fast but leaves them on the brink of exhaustion before they even get the chance to de-transform. Shadow and Sonic have both experienced this and almost died anyway after neutralizing the threat at hand. Furthermore, characters such as Tails and Mecha Sonic are so inexperienced with Chaos power that they need not only the Chaos Emeralds, but a secondary source (In Tails' case, the Super Emeralds and in Mecha's case, the Master Emerald) to even transform in the first place.
  • Final Fantasy:
    • Final Fantasy IV:
      • The sage Tellah is seeking the ultimate magic spell, Meteo(r), so that he can seek revenge on Golbez (the game's Big Bad) for the death of his daughter Anna. Sure enough, Tellah eventually learns the spell from his repressed memory, and uses it against Golbez, killing himself in the process. Other, more youthful mages, as well as an eternal precursor, can cast it without side effects. In gameplay terms, this means that he never ends up getting the required amount of MP to cast it.
      • In the DS remake, thanks to the New Game+ mode the game has, you can easily subvert this: while the items to raise your max MP wouldn't normally be accessible until after his death, they can be carried over from your previous playthrough and indeed, using one on Tellah will allow him to cast Meteor as many times as you want with no ill effects.
    • In Final Fantasy: The 4 Heroes of Light, the Crystal puts an ominous pause into its usual new-crown recitation by saying "To thee, I give this gift of light, upon thy head a crown of... forbidden might" when you get the final one, Dark Fencer. The Desolator spell obtained at the same time is treated in the same way.
    • Final Fantasy XIV
      • Louisoix uses a powerful imprisoning spell that is fueled by the aetheric power of numerous prayers in an attempt to rebind the Primal Bahamut before he causes more damage throughout Eorzea. However, the spell is so powerful, it drains every last ounce of aether within the caster using it and while Louisoix didn't use the spell fully as Bahamut broke free, it was enough to end his life as he stopped Bahamut. Papalymo, one of the Scions of the Seventh Dawn, does this to seal away a brand new Primal temporarily, dying in the process. It ends up being a Senseless Sacrifice since the new Primal, Shinryu, ends up escaping anyway to the point that Omega has to be used.
      • 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 Player Character being given a pass because they are the Warrior of Light. The disastrous results of the abuse of White and Black Magic also gave way to Red Magic, which is a more Downplayed take on this trope: instead of drawing aether from the planet, Red Magic 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.
      • Y'Shtola has this with the Flow spell. It's a dangerous teleportation spell where the user and anyone caught in it is scattered into the aether. It's not until midway through Heavensward that she's returned from it, but now having Prophet Eyes. Thancred ended up Naked on Arrival in the Dravanian Forelands, though now he can no longer use even the basic spells like Teleport or Return, rendering him an utter muggle. Minfillia ran into the Flow spell so she could become one with Hydaleyn. The second time she used it was in Shadowbringers to escape Vauthry's general, Ran'jit, and it was only thanks to Emet-Selch pulling her out of the aether this time that a crisis was averted.
      • The Ruby Weapon in Shadowbringers has "Oversoul". When activated, Oversoul grants the Ruby Weapon a power boost on the scale of a primal, but at terrible cost: the pilot is absorbed into the Weapon's core and forcibly transformed into a clone of whoever's fighting data is in the Weapon's data banks — in the case of the Ruby Weapon, Nael van Darnus.
      • In gameplay, there is the invincibility abilities used by the Dark Knight and Gunbreaker tank jobs, "Living Dead" and "Superbolide" (respectively). "Living Dead" allows a Dark Knight to survive otherwise fatal damage with just 1 HP while granting them invulnerability, but if their HP is not completely recovered within ten seconds of entering this "Walking Dead" state, they will die automatically. "Superbolide", meanwhile, grants immediate invincibility for eight seconds, albeit at the cost of reducing their HP to 1, leaving them in a very vulnerable state if they cannot get healed quickly.
  • The Dragon Quest games have two such spells. One is Kamikazee, which has a near guaranteed chance of utterly destroying anything that isn't a boss. The other is Kerplunk, which revives the entire party and restores them to full health. Both of these spells will kill the user.
  • Suikoden IV offers us the Rune of Punishment, which drains the user's life every time it's used. The rune itself is sentient and tries to engineer events around it to guarantee it will keep getting used, until eventually its bearer is killed and the rune jumps to a new host, only to begin the cycle anew. Interestingly, the Rune of Punishment governs atonement and forgiveness. if the player is able to forgive the resident backstabbing friend Snowe throughout the course of the game (and he becomes less and less worthy of forgiveness as time goes on, so it's tough) and recruit all 108 Stars of Destiny, Leknaat appears and says that the rune's time of punishment is at an end, and the time for forgiveness has arrived. In addition to unlocking the most powerful rune attack, which greatly damages enemies and greatly heals allies, the improved Rune of Punishment no longer injuries the user for attacks. This, of course, implies that everyone that used the rune before was either a) stupid and greedy, or b) unable to understand the proper implications of forgiveness. Compare the Soul Eater Rune in the first Suikoden game, which... eats souls.
  • Mega Man Battle Network:
    • In those games, the Dark Chips are extremely powerful, but that permanently reduce your max HP by 1 with each use. Also, each use drops your Karma Meter, and enough uses will disable Soul Unisons.
    • Battle Network 5 also has Chaos Soul Unisons, which allows you to use a Dark Chip as your charged shot for one round of battle without any of the permanent negative side effects. However, there is a noticeable chance (game-breaking glitch notwithstanding) that the charged shot will fail and backfire, instead summoning an invincible shadow copy of Mega Man to join the enemies and attempt to beat the crap out of you. Also doubles as Difficult, but Awesome, as enough use of Chaos Unison trains the player to be able to use it multiple times in succession without being knocked out of it without Pause Scumming, meaning the player can continue charging even if they're being pressed. Shadow Chaos, Knight Chaos, and Magnet Chaos are particularly deadly upon being mastered.
  • The World Ends with You:
    • Joshua uses his Jesus Beam attacks to get himself and Neku out of a battle with a Taboo Noise. Though not dangerous in itself, he held back this power until this moment to conceal his identity as the Composer, and used this power in the sight of a Reaper, thereby drawing suspicion to himself.
    • Late in the story, Kitaniji orders all the Reapers to wear special "O-Pins", which Uzuki gleefully describes as granting "unchained power". Kariya points out that there's probably a good reason the chains are normally kept on. Subverted; as Konishi managed to figure out, Kitaniji lied about what they do. There's no power boost at all, they're just part of his Assimilation Plot.
    • Hanekoma later proceeds to revive Minamimoto as a Taboo Noise He reveals this himself to the player in the secret reports.
  • Some Techniques and Spells in Romancing SaGa drain Life Energy if one is low leveled in That field of magic or if the weapon uses Life Energy for its techniques.
  • Valkyrie Profile: Covenant of the Plume has a heartbreaking example in the Destiny Plume. Left by Lenneth on Wylfred's father's body and corrupted by the goddess Hel, it can make any unit absurdly powerful - ten times as powerful in every single stat. And at the end of the stage, they die. Wyl is forced to use its power on his best friend and would-be Lancer at the beginning of the game...
  • Castlevania:
    • In Castlevania: Portrait of Ruin, it's stated that if anyone outside the Belmont clan uses the true power of the Vampire Killer, it will drain their life force and eventually kill them if they overuse it. When the whip's power is unlocked in game, it can be used as much as you want with no negative consequences gameplay-wise, but it's likely that it would simply take longer than the few days the game seems to take place over for it to take a serious toll.
    • Castlevania: Order of Ecclesia has the Dominus glyphs; Dominus Anger and Dominus Hatred are direct attack glyphs that are incredibly powerful but take off a solid chunk of your HP, while Dominus Agony massively increases all your stats at the cost of constant damage over time. Unless you use a healing item at some point, prolonged uses of these glyphs by themselves will kill you. The Dominus glyph union outright kills everything in the area—Shanoa included...unless you're using it at the end of the final battle, when Albus lets his soul be the sacrifice instead.
  • Breath of Fire: Dragon Quarter had an extreme version of this. The main character, Ryu, can transform into a ridiculously powerful dragon form at any time which can even floor bosses in a few attacks. However, there's a % counter in the top-right corner of the screen that's slowly ticking towards 100% throughout the game, and using dragon powers make the counter increase much more quickly than it normally does - and if the counter gets to 100%, it's game over. Without dragon powers, the boss fights are quite hard (especially the later ones), so it's down to the player to manage how often they use the dragon powers.
  • Vagrant Story has learned techniques that, when used, drain a portion of your health.
  • Akuma's (Gouki in the original Japanese) fighting-style from Street Fighter has the Shun Goku Satsu attack. Until it was mastered by Akuma, it was generally assumed that using it would always be lethal to both. Of course, in-game, it's just a move that does a lot of damage...
  • Team Fortress 2: There is an unlockable weapon for the Demoman class called The Eyelander, a massive sword which decapitates and heals its user on a killing blow. The downside is that having the sword in your loadout reduces your max HP by 25 because the blade feeds on your soul.
    • Averted when, upon killing enough people with the eyelander, the Demoman becomes second in max health only to the Heavy and in speed to the Scout (or a Soldier with the Escape Plan at maximum effect).
    • A more appropriate example is the Equalizer. It's possible for a Soldier to do huge damage when wielding the melee weapon and at low health. Obviously while powerful, using the weapon this way is very risky, as a casual shot could kill the soldier. Oftentimes cornered soldiers with no rockets use this tactic as a last resort.
    • Similarly, the Escape Plan increases the Soldier's speed when wielded as the user's health decreases, allowing the wielder to catch up to a Scout when at less than 20% HP. It also applies a Damage-Increasing Debuff to the user when wielded that persists for a few seconds after being wielded.
    • A sillier example is the close combat Ullapool Caber. Is it a giant log that takes health of the user when you swing it? No. It's a stick grenade, that you whack people with. It only works once, and you sure as hell are going to feel it if you don't have any bonuses because it explodes in your face. Despite the fact that you are dead if you come across another enemy, it's quite deadly, and can be useful as a last resort or for OHK Os with a critical charge.
    • The Boston Basher for the scout is possibly his most powerful DPS weapon, having no damage penalty or crit penalty while being able to inflict bleed damage. However, any attacks that make absolutely no contact will instead hit you, inflicting full damage and bleed on you. On a crit, this can kill the wielder in one hit (although not instantly, but the bleed will do him in if he doesn't find a medkit). If combined with the Crit-a-Cola, this can turn the user into a whirlwind of pain, so long as they never miss.
    • The Conniver's Kunai was designed with this in mind; it lowered the user's health so low that a glancing hit from any weapon was strong enough to kill the wielder. This is especially problematic because the class that uses it, the spy, is often in the midst of combat and very likely to get glanced even if the opponent doesn't know he exists. The perk comes that upon a successful backstab, the user gains all the health of the person he just killed. Skilled Kunai users can chainstab through an absurdly large amount of people that they can effectively tank sentries while this happens, which also helps that they also wipe out entire teams with this kind of a maneuver.
  • The first four .hack// games feature Data Drain, a technique that allows the user to either severely weaken a computer-controlled enemy, or Mind Rape a human being (most humans hit with a Data Drain end up in comas). The hero, Kite, is the only human with the ability. He uses it to weaken game enemies that have been hacked so as to have infinite HP, thereby making them easy to defeat and to gather virus data to hack into protected areas of the game. The catch is that repeated use will corrupt his character data with the virus, causing nasty side effects in battle and, eventually, his character's death.
  • Multiple moves in the Pokémon franchise harm the user (such as Explosion), but these moves also tend to be very powerful.
    • And then there's the move "Struggle," which is a rather weak move that damages the user by 1/4th of its max HP. Chances are, you're only using it four times before you die. And that's a base case scenario; considering that it's a move that only becomes available when all your other moves are out of PP, odds are it'll do even less than that.
    • Focus Punch is extremely powerful but at two costs. 1. It takes one turn to power up, leaving it open for attack. 2. If your pokemon is hit while powering up it "loses focus" and can't attack.
    • And, of course, the classic Hyper Beam and all of its variations. It has 150 base power but also renders the user immobile on the next turn.
    • There's also Curse and Belly Drum, where the user sacrifices half its total HP in order to have the foe lose 1/4 HP every turn or maximize its Attack, respectively. If the user uses the former when they have less than half HP left, they faint; the latter fails when the user is at half HP or less.
    • As of Generation V, there's a move called Final Gambit, which causes the user to deal its current HP to the enemy at the cost of fainting. It's also commonly suggested as the best move for Shedinja.
    • And then there's moves like Overheat and Close Combat, which, while powerful cause Stat drops to the user and leave them vulnerable to opposing attacks.
  • In NetHack, one can choose to break a magic wand in half, unleashing all the remaining power at once. Can be dangerous as most wands will simply explode.
  • In MLB Power Pros, Alvin has a special pitch, the Mirage Knuckler, but it is extremely dangerous to try to catch it, so much after Alvin and Mark, the catcher train with it for a week, Mark is covered with bruises.
  • In Valkyria Chronicles, Valkyrur are already so powerful that not only can they fire huge lasers, NORMAL BULLETS HAVE NO EFFECT ON THEM AND MORTAR ROUNDS CAN ONLY STUN THEM. However, they can sacrifice their life to do things on the scale of annihilating a fort, and the army inside it in a giant blue flame.
  • In Zettai Hero Project Dangerama's entire skillset is composed of these. As a Death Seeker, this makes sense.
  • Blood Magic is treated as this by most factions in Dragon Age. It is extremely powerful and dangerous — to enemies, allies, and the user — and is forbidden virtually everywhere outside Tevinter. While in theory, it's no more dangerous than regular magic, the potential for sacrificing or controlling others is considered too dangerous by almost everyone. Even the Tevinter Imperium officially condemns Blood Magic, though in practice all of the Magisters are secretly Blood Mages. The Grey Wardens don't officially forbid it, but many are still leery of it.
  • In Trauma Center: Under the Knife Derek's senior surgeon forbids him from using the Healing Touch after his first intentional use of it makes him collapse after the operation... with the caveat he's completely aware Derek will merrily ignore this instruction if he thinks the Healing Touch will mean the difference between life and death. This is meant to communicate to the player that they should only use it as a last resort, as doing so will negatively impact their score. Good luck figuring that out without trial and error, though. Although the only time that the Healing Touch is actually bad is in Under the Knife, where it slaughters your ranking. Any game from Second Opinion or later have no penalties to using the Healing Touch.
  • Dungeon Crawl has a lot of examples.
    • Lugonu's self-banish causes permanent damage to HP and MP.
    • As does Borgnjor's Revivification.
    • Most necromancy is partially cast from HP.
    • High-level summonings can break free and turn hostile at random, and those that can't will instead inflict nasty stuff like sickness and intelligence loss on the caster.
    • Downplayed with mid-level summonings, most of which have a chance to be hostile.
  • Zed in League of Legends is stated to have learned forbidden shadow techniques to defeat his rival Shen, and become a more powerful ninja. It mostly translates to throwing living shadows everywhere.
  • An antagonist example: In Golden Sun, shapeshifting into dragons seems to be a Dangerous Forbidden Technique of the Mars Clan of Prox, requiring a great deal of energy and completely wiping out the user's abilities afterward. Saturos even warns Felix in the first game that he and Menardi won't be much help after fighting Isaac & Co. as the Fusion Dragon (which they aren't, though not for the reasons Saturos had expected). When it's forced on the antagonists of Golden Sun: The Lost Age, they are left without enough power to warm themselves against the freezing cold of the Northern Reaches, and freeze to death. And then the Wise One forces the transformation on your parents...
  • The Binding of Isaac allows players to pick up many upgrades and abilities at random, some of which are very, very powerful. But there are many with heavy, even potentially crippling costs.
    • Ipecac changes one's tears into a strong explosive attack, at the cost of making them charge slowly and be able to hurt the player. In an added bit of irony, range up effects or upgrades actually make Ipecac harder to use, as maxed range makes the projectile detonate far from the player. This means they'd need to hug the opposite wall just to have a hope of hitting a target in the middle of the room.
    • The Suicide Bomber vest allows the player to use unlimited explosions, with the downside being they also take the damage. Because, you know, they are detonating bombs strapped to their chest.
    • The Devil Rooms usually hold a number of power items, and while they vary from room to room they're relatively consistent. The problem comes from having to sacrifice heart containers to receive them. Not hearts, heart CONTAINERS. The player literally sacrifices their life for power. And that's not counting many of the items they get from the devil rooms have their own disadvantages.
  • In each of E.Y.E.: Divine Cybermancy's three main endings, you are rewarded with a unique and hyper-lethal "Gate" psychic ability. The Hypnotic Gate instantly and permanently paralyzes an enemy, Triangular Gate warps an enemy out of reality, and Substitution causes the player to be healed if the enemy takes damage, and damage the enemy if the player is hurt. All of the abilities are also hyper-lethal for the user, as they have a very high probability to fling the user towards random directions at lethal speeds, drive them insane, fry their brains, or cause permanent trauma which hurts stats and persist even after resurrector usage.
  • Ikaruga: "Release the restraint device. Using the released power may result in destruction of the ship".
  • In the background lore for Diablo III, the Wizard character is doing this when he or she expands his/her arsenal to include the manipulation of raw mana and controlling time, as well as when s/he ignores the normal rules about Equivalent Exchange that other casters adhere to in order to prevent magical fallout or corruption. This is why the Wizard is much more destructive than the Sorcerer/ess of the past two games.
  • The Hell Stringer Technique of the Orphes in Super Robot Wars UX is basically a combination attack with the Lyrath that uses the Lepton Vector Engine. Richard uses it to bend the space-time continuum, so he could survive. Richard's body was already screwed up by then and that use pretty much was the final nail.
  • Odin Sphere has Oswald's shadow form. In gameplay terms, it vastly increases his attack speed and power, at the cost of rapidly eating away as his POW meter (which, if depleted, causes him to become exhausted and unable to move or attack until it refills completely.) In story terms, using it too much will destroy Oswald's soul and turn him into one of the ghostly Revenants haunting Winterhorn Ridge which eventually does happen in one of the bad ending scenarios, is Oswald is pitted against Onyx.
    • There's also the Darkova spell, which transforms the user into a massive, powerful Cerberus. The former king of Titania used it once to try and fend off enemy forces and went mad with power, ravaging Titania for seven days until he was finally slain by his son. Ingway finds out how to use it, and it similarly comes back to bite him as soon as he does.
  • In The Elder Scrolls Redguard warriors known as "Sword Singers" could become so skilled with their blades that they were said to be able to split atoms using a technique known as the "Pankratosword." It is said that their original homeland of Yokuda was destroyed by this technique, so it became forbidden and was lost to history. (Though the "destruction of the homeland" story is hinted at being an embellishment, and the Redguard people left Yokuda to escape much more traditional violence and oppression.) This being The Elder Scrolls, where lore is often intentionally contradictory, it is left up to the audience to draw their own conclusions.
    • The Bosmer have a much more well-documented technique known as the Wild Hunt where they call upon the power of their patron god to turn into horrifying, berserk creatures that kill and consume everything in their path. However, the transformation is permanent, and changed Bosmer are so consumed by their hunger that they will literally eat each other if no prey is readily within reach, meaning that Wild Hunts usually end with a "cannabalistic orgy" (as described by one In-Universe writer) once the affected Bosmer kill and consume every other animal or person they can find. Bosmer are deeply ashamed of using the Wild Hunt, to the point that it is only used in the most dire of circumstances and there are only two documented instances of it happening in recent Tameriel history; to its credit, however, both uses achieved the desired goals.
  • A few heroes in Dota 2 have abilities that are like this. Some examples are Huskar's Life Break, an ability that will deal 35% of an enemy's current HP as damage, but will do the same thing to Huskar himself, and the Techies Suicide Squad, Attack!, which will kill the Techies with a massive explosion, but will also deal massive damage to any enemies in the explosion's radius, if not kill them outright.
  • In Darkest Dungeon, the Jester class has a move called Heroic End that would be better classified as a harmless forbidden technique. However, in the Deepest Dark mod, this attack gains incredibly high offensive bonuses against every status effect on the target. The catch is that if there are no status effects on the target it's not much better than a normal attack and using this move at all stuns, debuffs, and marks the user for 3 turns, ensuring anything that survives will focus their attacks on him and kill him before he recovers.
  • Copy Kitty: The Bonus Boss of the game is a techno-magical abomination that wields the ultimate dark magic spell, something called the "Vestige of the Lost". However, even the boss cannot control the full spell and has to split it into three components which it channels through orbiting altar-like enemies. To defeat the boss, Boki has to copy all three component powers and then combine them to unleash the spell's full power. The result is not pretty, though fortunately this all happens in a simulation, so the worst that happens is the sim crashes and Boki gets knocked out.
  • The Satsui no Hadou ("Surge of Murderous Intent") from Street Fighter; a dark ki that fighters seeking victory and power can call upon should they be willing to fight without mercy. Gouken hated this aspect of his fighting style and created a fork that does away with it in order to promote humanity and personal growth through martial arts. Despite that, Ryu constantly struggles to avoid succumbing (the endgame being the "what if" character Evil Ryu) and Gouken's brother Akuma has embraced it, despising Gouken for teaching a "softened" art (though he is not entirely in control of it, as Oni demonstrates can happen if he relies on it too much). Techniques that draw upon the Satsui no Hadou are themselves Dangerous Forbidden Techniques; being the Metsu Hadoken, Metsu Shoryuken, and Shun Goku Satsu (the last one potentially being lethal to both the victim and user, depending on the contents of the user's soul).
  • Battle Garegga lets you "reprogram" autofire by manually tapping the fire button for two seconds to "record" a new autofire pattern, and you can raise the rate of autofire this way. However, raising the autofire rate will multiply the rate at which rank increases over time, as explained here, and the rank increase rate cannot be reduced once you raise it, meaning that attempting to give yourself faster autofire in the early game can spell disaster in the form of ridiculously aggressive enemies later on. It does have its applications, but those are left to advanced players who seriously know what they're doing.
  • Stellaris: There are some really special technology pathways which if researched grant your star empire some exceptionally powerful bonuses but could also have potentially disastrous consequences for the entire galaxy. Playing with psionics, for instance, can net you Expies of Jedi and Navigators, as well as upgraded versions of the best starship drive in the entire game, but may also lead to an invasion by very hungry Energy Beings from another dimension. Pursuing the development of robots and AI can lead to pops which can survive on any planet, aren't affected by happiness ratings and have increased production of every resource, but will push for synthetic civil rights as you climb up the Sliding Scale of Robot Intelligence and you can even end up with a Robot War if you have too many disenfranchised synthetics in your empire.
  • Familiars of Witches in the world of Wadanohara have an ability like this, giving them a massive power boost after drinking their witch's blood, however abusing the power is stated that it will kill the Familiar. This is first demonstrated by Chlomaki having Lobco to kill a huge amount of Tosatsu kingdom warriors in one go. It is later used in the true ending, when Samekichi needs to go into the Sea of Death to close the gate and can't be certain that he will make it with his own power. Wadanohara has been stabbed already, so he takes some of her blood so that he will be strong enough to do his mission.
  • Utawarerumono: Kuon in the sequels has her divine blood. As she is the daughter of Uistalnemetia's human host, she has access to the god's powers and is theoretically capable of a level of power surpassing even the Big Bad. However, every time she uses even a small amount of it, it leaves her utterly exhausted and feverish, and when she does try to use it in full, it's far too much for a mortal spirit to handle, and she winds up being possessed by Uistalnemetia's dark side. At that point the rest of the heroes require a literal Deus ex Machina to save her.
  • Eternal Twilight: The setting features many varieties of magic, but Blood Magic is the most powerful in offense and manipulating life. However, using it causes one's sanity to erode and the soul to be tainted.
  • Zeno Clash: The "Trick with the Bomb". It's simple: the user takes out a skull bomb, pulls the pin, and holds it up to their attacker's body, letting the blast take them both. Ghat can survive this, though it's extremely painful. Most of his enemies can't.

    Visual Novels 
  • In the Fate scenario of Fate/stay night, Saber comes under this limitation because using her Noble Phantasm requires all the mana she's currently holding to activate (and her flawed summoning means Shirou can't provide her with any), and she ends up facing at least three enemies that require — or at least seem to require — the use of it to defeat.
    • In Heaven's Feel, projection (more specifically, projection using Archer's arm) becomes this for Shirou. While it puts a strain on him in all three paths, this path specifically gives him a clear limit on usage, and overuse will kill him. Which it eventually does.
    • Furthermore, each Servant has a power known as the Broken Phantasm — willingly breaking their Noble Phantasm. This renders the servant without their proof of heroism (which for many of them is their weapon) but also inflicts massive one-time damage on whoever the Phantasm is shattered on. Archer, who can create Noble Phantasm duplicates, routinely uses this technique to compensate for the fact that his duplicates are weaker than the real thing.
  • The protagonist of Tsukihime has the Mystic Eyes of Death Perception, which allow him see the concept of death itself on everything in the form of lines and points. Observing death, however, will lead to insanity, so he has to use special glasses which block his ability. Every time he takes off these glasses his eyes get stronger, but since humans are not meant to observe the nature of death it puts an increasingly enormous strain on him. In fact, in the epilogue, which takes place a while after any of the routes, it is revealed in his reunion with his 'sensei' that he is literally on the verge of death, in part due to his ability; it is heavily implied that he actually dies just after they part ways.

    Web Comics 
  • MS Paint Adventures and Problem Sleuth both feature SEPULCHRI-TUUUUUUUUUDE!!
  • 8-Bit Theater:
    • HADOKEN!!!! Although not considered forbidden, Black Mage is only able to cast that spell once a day, and it makes a cute little nuke-sized crater wherever he aims it.
    • Spells that drain the net amount of love from the universe with each use and require the sacrifice of orphans to gain in the first place tend to have a bit of a social stigma against them. Black Mage seems to find an excuse to use it nearly every day...but then again, this is Black Mage.
    • Also, the Ice-9 spell, which was purely theoretical until Red Mage used it to defeat Kary, the Fiend of Flames. No one had ever cast it up to that point because it would put everything in existence on ice. Thankfully, RM had a Bag of Holding which contained both Kary and the spell.
  • Last Res0rt: Jigsaw Forte's Zombie Mode, while not explicitly a Dangerous Forbidden Technique, effectively becomes this when you realize if she uses it at all while on camera, she's blown her personal Masquerade (which means if she doesn't die from using it in the first place, she will when she's done). Word of God implies that abusing the form does have plenty of consequences, but it depends on how she uses it / how much damage she sustains, not necessarily how often.
  • In El Goonish Shive, magic apparently drain users at various rates. Spells too powerful to handle may overtax even well-trained magic users, possibly even removing their magic for months at a time.
  • The Forbidden Move in Axe Cop Gets Married: When Axe Cop's opponents at a fighting restaurant in China do a secret move that combines them all into a giant fighter, Axe Cop counters that he knows a move that is more than secret — meaning because it's forbidden. The technique has not been explained as forbidden before, but everyone knows about it and panics when he starts to do it because it will kill everyone in two provinces. The move creates a giant tornado that picks up the adjacent province and smashes your opponent with it. Ultimately subverted: Axe Cop shows that when done correctly, the move only affects the one opponent, removing everyone and everything else to safety and then putting them back too fast for anyone to notice.
  • Jacob from Demon Fist can teleport, but doing so damages his body. Using the power to escape with the Hookshot was what cost him his hand.
  • The Shield of Wonders from Goblins is an Artifact of Doom that casts random magical effects when struck. Simply using the Shield in combat is a Dangerous Forbidden Technique since it's barely less dangerous to the user than it is to his enemies. Naturally, Complains is forced to use it profusely in a Death-or-Glory Attack, and naturally the shield almost kills him a couple of times and turns him into a half-demon.
  • In Heartcore, we have Blast Bomb, Volaster's most powerful spell: upon letting himself be injured to the point where he is bleeding out rapidly, Volaster uses his salamander demon blood to turn himself into a Fantastic Nuke. In addition to killing himself in the blast, it also damages his Heartcore, which causes his offspring/successor, Carval, to suffer from stunted growth.
  • Illusion magic in Another Gaming Comic. In the group's backstory, the use and abuse of illusion magic had reached the point where the players were forced in simple self-defense to specifically and explicitly test every single thing they encountered to confirm that it wasn't an illusion, slowing the game to a snail's pace and driving the GM to dangerous levels of fury. In the end, the problem was only stopped by the signing of The Treaty, an actual real-life, notarized treaty that banned the use of all forms of illusion.
  • Unsounded: "Core Leeching" is a purposely incomplete spell that causes the Background Magic Field of the Khert to see the target as "bad data" and erase it from existence. It's both illegal and terribly bad form because it has no tactical advantage over other spells, makes Magic Misfires more likely in the area for a while afterward, and invariably causes a horrifically Cruel and Unusual Death.
  • Kill Six Billion Demons has entire Supernatural Martial Arts styles consisting of this. The angel 82 White Chain normally uses Empty Palms, but against an especially dangerous opponent can break out Krayu Mat, a style intended for facing demons and gods, rarely used because of the immense physical and spiritual strain it requires. It's noted that a human trying to use it would utterly annihilate their own body. There's also Ki Rata, a 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.

    Web Original 
  • There are several different levels of it in the Whateley Universe. Phase has a technique (using his disruption-light level on someone) that runs the risk of corrupting their Body Image Template if they are an Exemplar or Shifter, and turning them into something grotesque; he avoids it on moral grounds. Fey has some spells powerful enough that the energy drain will destroy entire ecosystems around her, which is way worse.

    Western Animation 
  • Ben 10: Ultimate Alien: Osmosians are aliens that can absorb matter and create something out of that absorbed material (usually armor). They can also absorb energy, but it can turn them Ax-Crazy. To elaborate, Kevin absorbed energy from Ben's Ultimatrix to stop Aggregor's plans of bringing forth the End of the World as We Know It. They defeated him alright, but afterward Kevin went as far as ruthlessly killing whatever comes his way in a rampage out of insanity. He was so insane his wrongdoings can be classified as Nightmare Fuel.
  • Avatar: The Last Airbender and The Legend of Korra:
    • While it's not really forbidden, lightning redirection (a Firebending technique where you internalize lightning and shoot it in another direction) is extremely dangerous, to the point where even teachers of the move refuse to practice it with their students. First, you have to catch the lightning, which is just as dangerous as it sounds. While internalized, the lightning must be carefully controlled so it doesn't travel through vital organs. By the end of the series, only three characters know the technique, and only Iroh is skilled enough to avoid the dangers consistently.
    • Bloodbending, supposedly the ultimate technique of waterbending, which involves moving around the blood in a living body and making that body do whatever you want it to do. Like the Osmosian example above, it is shown that it is detrimental to the Waterbender's sanity, making them Ax-Crazy and power-driven. To elaborate, Hama was bent on getting revenge after discovering the technique, Katara almost lost herself while trying to avenge her mother, in which she almost lost control while mercilessly bloodbending the Fire Nation's Guards. Unlike the first two, it's apparently quite easy to learn, at least for a master; it's mostly a matter of being willing to do it once you learn it's possible. Later on in The Legend of Korra, it's revealed that bloodbending has since been outlawed completely and for good reason, as it turned out a mob boss learned the technique and used it to effortlessly control people whenever he liked. Even more disturbingly, this is also the source of Amon's ability to remove someone's bending.
    • Energybending, a technique from before humanity first bent the elements, also carries the danger of mentally and spiritually destroying those who attempt to use it on others if their willpower isn't strong enough. This nearly happened to Aang when he used it on Ozai.
  • In He-Man and the Masters of the Universe (2002) there was the Spell of Separation. Thousands of years before the present day, Hordak used it to divide Eternia into the Light and Dark Hemisphere's, hoping it would transform the Dark half into a realm where he could raise his dark army. But it was more powerful than he had thought and might have rent the entire planet in two if he hadn't realized it in time and put a stop to it. In the present day, Two-Badd gets ahold of the spell and believes it can be used to separate them back into their original forms of Tuvar and Baddhra; ignoring He-Man's warnings when he tries to stop them, they gather the three artifacts they need, and the spell is restarted where Hordak left off, forcing He-Man to push himself to his limits and return the three components before it literally destroys Eternia.
  • In W.I.T.C.H., the Guardians can choose to transform into living embodiments of their elements, giving them Physical God levels of power- at the risk of losing their personalities and humanity, and being left open to mental domination from outside forces, such as Big Bad Nerissa. Fortunately, the one time they do this, they manage to come back- barely.
  • ReBoot: Bob's fusion with Glitch is viewed as doing the unthinkable by Daemon's adviser, and Bob was fully aware that overusing his new Glitch powers would kill him. Bob comes very close to death when Daemon infects and forces him to overuse his powers to create portals. Bob does imply that the fusion would have been much less dangerous had Glitch not been damaged at the time (which is what necessitated the merger in the first place), however.
  • Transformers examples:
    • In The Transformers, Elita One turned out to have the power to freeze time, but as Alpha Trion had warned her, using it drained her Life Energy to a near-fatal level.
    • Also in Transformers: Generation 1, Megatron has the ability to draw anti-matter from black holes and pretty much blow up all of his surroundings. It was used about twice in the Marvel comics, where it was explained he didn't often use it because he was liable to kill himself too.
    • G1 again, Windcharger can create magnetic fields capable of ripping apart even the strongest of metal structures. It burns him up very rapidly though.
    • In Transformers Cybertron, Vector Prime would greatly tax himself reversing time by a few minutes, and eventually die by using his time/space powers to get the team through the rift separating Gigantion from the normal universe.
  • In Justice League the League had pretty much lost against the Brainiac/Luthor hybrid, until The Flash saves the day by running at extreme speeds (to the point where he was circling the world in mere seconds) and smacking Brainithor around by repeatedly running into him. Soon enough, he destroys all traces of Brainiac, leaving only a naked Luthor lying on the ground. However, in the process, he was almost swallowed by the Speed Force from moving so fast, and he says he probably won't be coming back if he ever goes that fast again.
    • In another episode, Flash and Luthor get their minds swapped, and Luthor!Flash is able to run rings around the rest of the League on the Watchtower, in part because he's willing to use superspeed power tricks (such as vibrating objects enough to shatter them) that Flash normally avoids as too dangerous.
  • A Batman: The Animated Series episode has a ninja steal a scroll in Japan that teaches him the secret of a "deadly touch" technique. When Batman faces him off in the end, he tries to avoid being touched by the guy in a specific spot, which (theoretically) would cause instant death. He fails and falls down, seemingly dead. He then gets up and knocks out the bad guy. When asked if the technique was bullshit, he pulls out a metal plate from under his suit, which has been deformed by a strong force.
  • On Regular Show, Muscle Man enters a bodybuilding contest, but since he doesn't have time to be fully fit, he concentrates on posing technique. As a last resort, he tries to execute a pose called the Shredder, which if done correctly, will "shred" the competition; but if done incorrectly, it causes the poser to explode. Muscle Man manages to do it perfectly and wins the competition.
  • Miraculous Ladybug: The Rabbit Miraculous allows its bearer to travel back in time and rewrite history, making it one of the single most powerful Miraculouses. The downside is... well, you're rewriting history. For this reason, the Rabbit is a "hero of last resort", only brought in when all other heroes have failed.
  • Dangerous Forbidden Technique: The Scrolls of Forbidden Spinjitzu from Season 11 make one's Spinjitzu more powerful but corrupt the user's personality as well. It is one of these scrolls, combined with amnesia and Vex's manipulation, that causes Zane to become the tyrannical Ice Emperor for decades in the Never-Realm.
  • Young Justice: Using the Helmet of Fate is this, because Nabu, the Lord of Order, wants a permanent host rather than have his power be used temporarily. Kid Flash and Aqualad both avoid this fate thanks to the spirit of Kent Nelson, the previous wielder, convincing Nabu to let them go. However, when Zatanna uses the helmet to stop Klarion, Nabu chooses her as his next wielder, and had already forced Kent Nelson's spirit to move on. The only reason she was released was that her father Zatara negotiated her freedom by offering himself as the next Doctor Fate.

    Real Life 
  • Backfired with the destruction of HMS Invincible at Jutland. The Dangerous Forbidden Technique, in this case, was the bypassing of safety protocols designed to prevent flashdown of a detonation in a turret from reaching the magazines, and it was done to increase the rate of fire. But Invincible was pounding the crap out of the German SMS Lutzow, so why not? Why not, indeed. The mist that was hiding her cleared, just long enough for the critically damaged but afloat Lutzownote , along with a second German battlecruiser SMS Derfflinger, to get some solid hits in the right place, and Invincible was blown in two. At least one and possibly both of the other British battlecruisers lost that day went up for the same reason. The fact that British ships of World War I used more volatile gunpowder than their German counterparts didn't help, either.
    • Similarly, many tanks have manually- or power-operated doors separating the ammunition locker from the turret, to keep a strike that penetrates the locker, or an onboard fire, from cooking off shells and killing the crew. Sometimes these doors will be disabled or removed to increase the rate of fire, but it's obviously not an approved practice.
  • 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 usually incapable of penetrating a cruiser's armor, one hit set off eight torpedoes, each with a 1000-pound warhead and a tank full of pure oxygen propellant. The resulting explosion knocked out the engines and the Chokai had to be scuttled.
  • The Mordhau note  in German school of swordsmanship. Bilingual Bonus applies why it is forbidden in friendly combat where the aim is NOT to kill your opponent. True, it may seem odd how, in a fight with big, sharp implements it's smashing someone with the handlenote  that's forbidden, but that thing is heavy, and tends to ignore the fact the victim's wearing metal armornote . It has that name for a reason.
  • In soccer, the awesome techniques of jumping up in the air and trying to hit a ball next to another player is usually forbidden, because it could hurt the other player if he'd get hit by a flying boot. A little more mild, but still similar is the "scissors" technique of scoring.
  • Nuclear weapons. Nukes are capable of great destruction, but actually using one comes at a hefty price. Large nuclear detonations release irradiated material into the surrounding environment that remains dangerous long after the explosion is over. In a more immediate sense, several nations have active nuclear weapons that are kept ready for launch at all times. Since there is currently no viable way to defend against a nuclear weapon after it's been launched, the target has no reason not to fire all its weapons at the aggressor. This is the concept of Mutual Assured Destruction (MAD) and it effectively makes using nukes suicidal. Note that in World War II, this was not an issue; with no other nuclear-capable countries to provide the "Mutual" portion of MAD, the United States was free to attack Japan without fear of similar retribution.
    • Though eight nations are declared to have nuclear weapons (and one is suspected) most nuclear powers refuse to consider using nuclear weapons unless someone else does first. Nowadays, the worry is more about the dangers of non-state actors (ie. terrorists) using them instead, which MAD is essentially powerless against.
    • Even nukes aren't necessarily as repellent as biological warfare. At least a nuclear weapon only destroys its targeted area, however horribly; use of biological agents as weapons poses a very real risk of infecting everyone the contagion touches, be they enemy, ally, innocent bystanders, or one's own side.
  • This trope is usually defied in real life, due to Combat Pragmatism being a time-honored military and general combative doctrine. If it's dangerous and highly lethal, using it is the best way to win. If it's forbidden, all the better because that means the other guy will never see it coming.
  • There are international Laws and Customs of War, that ban war tactics such as shooting the medic and deliberately harming civilians
  • Overdosing on caffeine as a deadline draws nearer.
    • Recreational drugs in general, actually. The more intense a drug's effects are, the more likely it is to cause harm if not moderated, along with the need for more strict moderation. And the more intense effects you experience, the more curious you'll get for even stronger experiences. Though just because an experience is weak doesn't mean the damage is light: air duster as an extreme example. Alcohol is an aversion, though: drinking more after getting buzzed actually decreases the euphoria and eventually can cause severe depression and rage.
  • There's a popular recipe among Russian students which consists of mixing 50 ml of Coke with 2 teaspoons of granulated coffee. Due to how it works on your body (Coke pretty much expands your blood vessels and makes caffeine go into the bloodstream much faster, multipliplying its effect), it can give you a huge energy boost for 8 to 14 hours. On the other side, even a single cup can have some harmful effects on your health, from high blood pressure to body tremors, not to mention that it's a guaranteed way to ruin your sleep schedule.
  • Not exactly a technique, but human muscles are actually so strong that they can rip themselves off your bones. Usually, the body has all kinds of limitations on itself to prevent it from happening, like pain. But in situations where super strength is the meaning of life or death (like being slowly crushed under some heavy boulder), the body can drop these limits by itself. It'll save your life when needed but at a really really painful cost. It will eventually heal, if you're able to find a doctor who can properly set your broken bones and muscles so that the ligaments and tendons heal naturally. And, also, you'll need to follow his protocols for recovery to the letter.
  • Steroids, blood doping, performance enhancing drugs and other methods are illegal in most official events, partly for this reason.
  • Water methanol injection, also called as War Emergency Power, on turbocharged internal combustion engines. Injecting 1:1 water-methanol mixture to the combustion chamber can boost the performance of the engine for up to 33% and add up extra horsepowers. It basically acts as a chemical intercooler. Unfortunately, its prolonged use (we speak about minutes here) will also damage the cylinder heads. In WWII, its use was approved only for emergency situations, like an airplane escaping from a particularly nasty enemy, and using the mechanism involved on breaking the seals. On Allied planes, this 'seal' was a thin wire stretched across the throttle assembly at the point where WEP would engage. The wire was strong enough to prevent a pilot from accidentally activating WEP, but could be broken fairly easily if the pilot deliberately pushed the throttle; the idea was, when the mechanics back at base inspected the plane after a mission, they would check this wire. If the wire was intact, the engine was okay, but if it was broken, then the mechanics knew the engine would have to be pulled out of the plane and rebuilt.
    • Likewise nitrous oxide injection called ''Ha-Ha-Gerät'' in the Luftwaffe, which acts as a chemical turbocharger. It will boost the performance, but long periods of use will seriously damage the engine.
    • This is the effect of pushing the engine past its rated limits. What's on paper is what the manufacturer has safely determined the engine will go up to without dying sooner than how long it's expected to last. You could always push an engine harder, but doing so wears it out faster. Sometimes much faster, if the strain you put on the engine passes what its structural integrity can handle, causing it to tear itself apart or burst into flames.
    • In modern military aircraft, afterburners can certainly count in some cases. The way they work is by taking raw jet fuel from your tanks and spraying it directly into the VERY hot exhaust section of the engine. This, in turn, adds up to a sudden burst of power from the engine which will get your aircraft from just barely scratching the sound barrier to moving twice the speed of sound in the span of a minute or so depending on the aircraft. This comes at a price, however. Normally, afterburner use is relegated to take off, or on a bolternote . These short bursts normally don't do much damage to the engine, but using it too often (as in the case with most dogfights), can shorten the life span of your engine, meaning it'll have to be changed out once you return to base. However, use the afterburners too much, and you won't even have to worry about that, because your aircraft will eventually clunk into the ground with not even a drop of fuel left in the tanks.
  • 'Cooking off' grenades involves pulling the pin and allowing it to tick closer to detonation before throwing it to the target. Successfully pulling it off results in the grenade exploding mid-air, showering the enemy with shrapnel while giving them less time (if any) to pick it up and throw it somewhere else. Failure results in the grenade exploding in your hand, which is unpleasant, to say the least. The fuse of a grenade is not so exact that you dare do this; there's enough wiggle room that you (and any member of The Squad standing too close) can be reduced to Pink Mist while you think you still have a little more time. And if you happen to get shot, lethally or not, with a cooked grenade in your hand...
  • Overclocking a PC's CPU can help squeeze in a performance boost, but this is not something to be done casually; without a good cooling system to offset the increased generation of heat, overclocking is a good way to ensure that you'll be shopping for a costly replacement CPU.
  • Believe it or not, there is one when playing pinball: The Bang Back technique involves giving a nice solid punch to the bottom of the machine. When done as the ball is traveling down the left outlane and into the drain, you can potentially save it and continue playing. Doing so, however, will probably hurt your fist and damage the machine with it. Even more so during the time manufacturers installed nails onto the bottom to impale the hands of players who attempted this. Nevertheless, the potential harm the Bang Back can do, as well as the technique allowing you to keep playing for far longer than is intended, means even attempting one is grounds for instant disqualification at all tournaments, big or small.
  • Bee's stings. They cause enough pain to their victim that they're either out of commission or deterred from attacking their hive. They also involve the bee's stinger embedding itself in the victim's flesh dragging the poison sac (and several vital organs) along with it, killing the insect. For this reason, bees only sting in response to a serious threat to their hive or queen.
    • However, this only applies to certain kinds of bees. While not wasteful of their stings, other bees CAN live after stinging. (It's also worth noting that this only occurs in (a subset of) those insects that are scientifically classified as bees; other types of stinging insects, though they are often referred to coloquially as "bees", are not true bees and do not have this limitation.)
    • This only applies to vertebrates, however. Bees can sting *insects* with impunity as their stingers have no problems with exoskeletons. They just get stuck in fleshier victims. Their (lack of) aggression has more complicated evolutionary origins and depends largely on the individual species.


Video Example(s):

Alternative Title(s): Forbidden Technique, Dangerous Technique, Forbidden Dangerous Technique


Harry Potter

Alastor 'Mad-Eye' Moody demonstrates to the students the three Unforgivable Curses: Imperio (the Imperius Curse), Crucio (the Cruciatus Curse), and Avada Kedavra (the Killing Curse). These three spells are known as such for being the most powerful and sinister spells known to the wizarding world, and their usage on another human being would often warrant a life sentence to Azkaban.

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Main / DangerousForbiddenTechnique

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Main / DangerousForbiddenTechnique