History Main / DefenceMechanismSuperpower

Compare DieOrFly and some cases of TraumaticSuperpowerAwakening, in which a power is initially discovered in this way, but can be used freely thereafter. If the superpowers attained are related to the specific nature of the danger, it's an AdaptiveAbility. May overlap with HeroicSafeMode which is more about how existing powers are used than new powers. See also, EmotionalPowers.

* ''WesternAnimation/AvatarTheLastAirbender'': The Avatar State starts out as this, presumably for every avatar. With effort and meditation, though, he or she can go in and out of it at will.

* In ''WesternAnimation/TheIncredibles'', Violet Parr gets a boost to her force field powers (effectively permanent until she dissolves them, probably six feet in diameter) when she and her brother, Dash, are threatened by the villain's mooks. Inverted earlier in the movie: when requested by her mother to [[spoiler:put a force field around a plane to stop them being blown out of the sky with ground-to-air missiles, she panics and is completely unable to concentrate and make one that's a) large enough to cover the plane or b) exists for more than a second]].

* In ''LightNovel/ACertainMagicalIndex'':

* Pacifica from ''LightNovel/ScrappedPrincess'' is only seemingly able to use her [[MakeMeWannaShout scream attack]] when under extreme stress.

* Kayneth Archibald El-Melloi of ''LightNovel/FateZero'' has this in the form of the Volumen Hydragyrum, an enormous bolus of mercury that (a) he [[MorphWeapon manipulates at will]] and (b) automatically defends him against threats.

* ''LightNovel/TheLegendaryMoonlightSculptor'': As a reward for completing an epic quest arc, the main character Weed unlocks a new class for players, the {{Necromancer}}, and is rewarded a high-level, as of yet unknown power from the class called The Power to Reject Death, allowing him, when he dies, to resurrect as a random member of TheUndead class of monster with new stats and powers until he either dies again or until 24 hours have passed and he returns to being human. In addition, some of his revivals grant him full-on control of necromancy skills, while his class type is normally locked out of any variety of sorcery.

[[folder:Light Novels]]
* ''LightNovel/TheLegendaryMoonlightSculptor'': As a reward for completing an epic quest arc, the main character Weed unlocks a new class for players, the {{Necromancer}}, and is rewarded a high-level, as of yet unknown power from the class called The Power to Reject Death, allowing him, when he dies, to resurrect as a random member of TheUndead class of monster with new stats and powers until he either dies again or until 24 hours have passed and he returns to being human. In addition, some of his revivals grant him full-on control of necromancy skills, while his class type is normally locked out of any variety of sorcery.
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* In ''VideoGame/BugFables'', this happens twice to Leif. The first time, he initially thought he wasn't capable of fighting, as he was the scout in his exploration team, until an enemy sneaks up on him. He uses [[AnIcePerson ice magic]] to freeze it out of reflex, surprising himself as well as Vi and Kabbu. The second time, [[MadScientist Dr. HB]] is unable to identify [[spoiler: the cordyceps]] inside Leif, and wants to dissect him, resulting in him putting up a [[DeflectorShield Bubble Shield]] to keep him away. In both of these cases, once his reflexes awakened the respective abilities for the first time, he was able to use them at will afterwards.

* In ''VideoGame/GoldenSun'', [[PsychicPowers adepts]] have forms of [[ElementalPowers Psyenergy]] which unconsciously protect them when they need it. This is first demonstrated in a cutscene in ''VideoGame/GoldenSun1'' when [[spoiler: they first enter Kolima or Kolima forest. They discover that some crystals are raining from the sky and turned the villagers into [[AndIMustScream trees]]. They're knocked unconscious but are protected by a shield (which reappears in several other parts of the game to help avert ConvectionSchmonvection and the like)]]. They vow to make an attempt to master this unconscious power, but never actually learn to willingly trigger it.

* The Blowfish Avenger in ''WesternAnimation/TheTick''.

* In ''VideoGame/DiabloIII'', Leah's power acts like this in the first two acts, only unleashing when she is in serious danger. When she finds her mother Adria again, she starts learning to control it, becoming an able mage.
* In ''VideoGame/ValkyriaChronicles'', the powers of the Valkyria are activated only in life-threatening situations. The main Valkyria encountered through the game (as an enemy), Selvaria, was revealed to have ''stabbed herself'' to activate her powers. [[spoiler:Later on, when a major character on the player's side is revealed to have been a Valkyria as well, this translates in gameplay into massively improved stats that only activate when the character's health drops below 50%.]]

* In ''LightNovel/ACertainMagicalIndex'', Accelerator's PsychicPowers, named "Vector Change", make him basically untouchable: any kind of harmful object (fist, bullet, radiation, extreme heat, etc) that touches his body gets its vectors reversed and reflected away from him without doing him any harm. This is just its basic "setting", however. If he makes active use of his Vector Change, he can do [[SuperPowerLottery many other things with it]]. [[spoiler:Using Vector Change to the maximum extent possible]] can only be done by willingly [[spoiler:shutting off this auto-defense]], however; this fact was exploited by one villain to [[spoiler:land a successful shot on Accelerator that left him with crippling brain damage (he recovered... sort of)]].

Can be used in a similar way to AlwaysABiggerFish, with a cowering hero looking up to discover their aggressor has mysteriously been blasted into dust, and muttering innocently "Did I do that?".

** In the finale of ''Anime/DragonBallSuper'', Goku muses that this is how Ultra Instinct - Mastered seems to work. Unlike his various Super Saiyan forms, Goku can't activate the form at will. It's only when he's in a truly life or death situation, such as having his universe erased if he didn't win the tournament, that he's able to tap into the form's power.

** Since Stands primarily protect their user from harm, it seems that it's not uncommon for Stand Users to learn of their power in this way. For example, in the first episode of the ''Stardust Crusaders'' series, Jotaro demonstrates by attempting to shoot himself in the head at point blank range; before he even learns how to control it properly, his Stand, Star Platinum, responds autonomously by catching the bullet mid-flight.

* ''Manga/RanmaOneHalf'', titular character has the Neko-Ken technique. His mind "learned" it as a way to briefly escape his crippling [[WhyDidItHaveToBeSnakes ailurophobia]] when he's absolutely surrounded by cats and is unable to flee from them, turning ''him'' into a cat. It happens more often than you might think. While it makes him immensely powerful, lightning-fast, and savage, he still ''thinks like a cat'' while in that state, making it an UselessUsefulSpell that anyone with half a mind can thwart and defeat.

* In ''Manga/SoulEater'', Death the Kid has one of these, shown when he is in serious danger of being killed by [[OurVampiresAreDifferent Mosquito]]. The activation is involuntary, and appears to allow for a significant boost in power and healing serious injury. It was presumably [[spoiler: a function [[TrulySingleParent Shinigami allowed for]] so that Kid would be able to defend himself if put in mortal danger while still a child. The fact that Mosquito ''knew'' what Kid [[HumanoidAbomination really was]] - and mocks him for it - suggests he [[TooDumbToLive should have known better.]]]]

* Hana Asakura from ''Manga/ShamanKingFlowers'' posseses one of this. [[spoiler:After a close encounter with death,]] Hana was given by Hao the same Oni summon ability his mother Anna used to have; they will be released whenever Hana's life is in danger.

* Any member of the Franchise/GreenLantern Corps will be defended or kept alive by their ring when unconscious, regardless of the 24-hour limitations. This is usually with just a thin shield, but can be tapped to use real powers if conscious but trapped. Some Green Lanterns are even able to make their rings run solely on willpower from within. All other ringslingers share this power, and Sinestro corpsmen need to do this as a rite of passage.

* In ''Fanfic/ChildOfTheStorm'', Harry's protection from his mother, [[spoiler: which takes the form of a connection to the Phoenix, combined with DeathActivatedSuperpower]] - whenever he's in mortal danger, [[spoiler: dying or dead, the Phoenix]] protects him, usually fairly subtly (relatively speaking). First by protecting him from Voldemort's killing curse as a baby, then by incinerating Quirrell, the by ensuring that Fawkes came to his aid in the Chamber of Secrets and then by giving his PsychicPowers the nudge they needed to activate and send a distress call, triggering the events of the story, and in chapter 58, [[spoiler: scaring off Hera]]. Then, in chapter 71, subtlety is dispensed with [[spoiler: by resurrecting him, possessing him, and going on a rampage that kills at least a couple of dozen HYDRA Agents and several hundred Dementors.]]

* In ''WesternAnimation/TheIncredibles'', Violet Parr gets a boost to her force field powers (effectively permanent until she dissolves them, probably six feet in diameter) when she and her brother, Dash, are threatened by the villian's mooks. Inverted earlier in the movie: when requested by her mother to [[spoiler:put a force field around a plane to stop them being blown out of the sky with ground-to-air missiles, she panics and is completely unable to concentrate and make one that's a) large enough to cover the plane or b) exists for more than a second]].

* ''LightNovel/TheLegendaryMoonlightSculptor'': As a reward for completing an epic quest arc, the main character Weed unlocks a new class for players, the {{Necromancer}}, and is rewarded a high-level, as of yet unknown power from the class called The Power to Reject Death, allowing him, when he dies, to resurrect as a random member of TheUndead class of monster with new stats and powers until he either dies again, or until 24 hours have passed and he returns to being human. In addition, some of his revivals grant him full on control of necromancy skills, while his class type is normally locked out of any variety of sorcery.

* In ''Literature/HarryPotter'', this is how young wizards first manifest their powers prior to learning to control them. In Harry's case for example, his first memory of using magic is [[TeleportationRescue apparating]] away from some pursuing bullies. Other manifestations include shrinking the incredibly ugly sweater he was forced to wear until it no longer fit him and growing all his hair back overnight when the Dursleys had shaved him bald.

[[folder:Live Action TV]]

** 2.0 actually both subverts it and plays it straight. Chuck can only use it when he's not overly emotional, which means he can use it when he's not in danger. The moment things get stressful he can't use it, until he really needs to, at which point he emotionally either enters the eye of the storm (if somebody else is in danger) or has to use a calming mantra (if he's in danger).

* In ''VideoGame/ValkyriaChronicles'', the powers of the Valkyria are activated only in life threatening situations. The main Valkyria encountered through the game (as an enemy), Selvaria, was revealed to have ''stabbed herself'' to activate her powers. [[spoiler:Later on, when a major character on the player's side is revealed to have been a Valkyria as well, this translates in gameplay into massively improved stats that only activate when the character's health drops below 50%.]]

** The entire reason Aang survived becoming a HumanPopsicle for a hundred years is because he instinctively used the Avatar State and a combination of air and water bending. Spending the entire century trapped in the Avatar State kept him alive, but it also burnt up the extra vitality that being the Avatar normally grants, leading to a relatively early death in his sixties (technically 160's).

* In ''WesternAnimation/{{Gargoyles}}'', Fox is the daughter of Halcyon Renard and [[spoiler: Titania]]. Despite that, for the whole series she shows no signs of being anything other than a normal human. That is, until [[spoiler: Oberon tries to kidnap her newborn son, to which she screams and sends him through the wall with a blast of raw, magical force.]]

* The "fight-or-flight" emergency response state makes defence-mechanism "super strength" an occasional TruthInTelevision. When faced with life or death, the human body goes into survival at any cost mode. This includes producing adrenaline which boosts muscle strength, shutting down strength restrictions that prevent muscles from tearing themselves apart and releasing endorphins to prevent the sensation of pain. Net result: you can lift a car for several seconds, engage in a [[GoodOldFisticuffs fistfight with a bear]], and/or run far faster and longer than you normally can. There is a reason why we can't activate the fight-or-fight reaction voluntarily and it can only remain as a Defence Mechanism: The stress response halts or slows down various relaxed processes such as sexual responses and digestive systems to focus all energy on the stressor situation, which means that [[HeroicRROD prolonged stress responses may actually result in long-term bodily damage, like digestive disorders and the suppression of the immune system. If you constantly have your muscles in maximum power due to adrenaline overload, your muscles will eventually tear themselves from the bone, rip themselves apart, or even start to liquefy]]. Of course, the severity of the damage depends on the intensity of the stressor, how far beyond the limits one goes, and for how long.
[[/folder]]

* In ''Manga/OnePiece'', [[HeavilyArmoredMook The Invincible Pearl]] could manifest flames when he felt threatened, i.e. whenever anyone managed to put a scratch on him through his supposedly invincible defense. While screaming "DANGER!! DANGER!!"

In video games, this may come in form of a passive ability that activates when you get hit by an attack, or when the enemy's attacking you. Compare CriticalStatusBuff and DesperationAttack, where having low health/getting attacked a lot either gives you a buff or allows you to perform a powerful attack. Video-game bosses tend to [[Main/TurnsRed Turn Red]] when sufficiently injured. This is seldom explained in story terms, but in cases where it is, one common explanation is this trope.

* It could be said that [[ComicBook/IncredibleHulk the Hulk]] could qualify as having such a power, assuming that whatever's threatening Bruce Banner manages to anger him enough. [[SplitPersonality Some of the Hulks]] certainly see part of their purpose being to deal with anything that threatens Bruce.

** Due to RuleOfFunny, the only time this fails is when he jumps from a great height in ''Film/TheIncredibleHulk'' and ''Film/ThorRagnarok''; Bruce gets to faceplant messily, ''then'' [[HulkingOut he Hulks out]].

* The "fight-or-flight" emergency response state makes defence-mechanism "super strength" an occasional TruthInTelevision. When faced with life or death, the human body goes into survival at any cost mode. This includes producing adrenaline which boosts muscle strength, shutting down strength restrictions that prevent muscles from tearing themselves apart and releasing endorphins to prevent the sensation of pain. Net result: you can lift a helicopter for several seconds. There is a reason why we can't activate the fight-or-fight reaction voluntarily and it can only remain as a Defence Mechanism: The stress response halts or slows down various relaxed processes such as sexual responses and digestive systems to focus all energy on the stressor situation, which means that [[HeroicRROD prolonged stress responses may actually result in long-term bodily damage, like digestive disorders and the suppression of the immune system. If you constantly have your muscles in maximum power due to adrenaline overload, your muscles will eventually tear themselves from the bone, rip themselves apart, or even start to liquefy]]. Of course, the severity of the damage depends on the intensity of the stressor, how far beyond the limits one goes, and for how long.

* ''LightNovel/TheLegendaryMoonlightSculptor'': As a reward for completing an epic quest arc, the main character Weed unlocks a new class for players, the {{Necromancer}}, and is rewarded a high-level, as of yet unknown power from the class called The Power to Reject Death, allowing him, when he dies, to resurrect as a random {{Undead}} class of monster with new stats and powers until he either dies again, or until 24 hours have passed and he returns to being human. In addition, some of his revivals grant him full on control of necromancy skills, while his class type is normally locked out of any variety of sorcery.

* In ''Anime/NeonGenesisEvangelion'', if Shinji is in a particularly grave psychological threat, Eva-01 goes into "berserker mode" where it breaks off from its technological restraint and becomes a SuperRobot which is actually an EldritchAbomination that dismembers said threat [[{{Gorn}} in a quite savage manner]]. [[spoiler:The basis of the OmniscientCouncilOfVagueness' conspiracy is about ritualistically using this defence mechanism's RealityWarper capabilities to trigger TheEndOFTheWorldAsWeKnowIt InTheirOwnImage. Said defence mechanism is powered by the soul of Shinji's mother.]] Fitting, with how this series is based on Freud's theories about defence mechanisms [[spoiler:and maternal relationships]].

* In ''Literature/HarryPotter'', this is how young wizards first manifest their powers prior to learning to control them. In Harry's case for example, his first memory of using magic is [[RescueTeleportation apparating]] away from some pursuing bullies. Other manifestations include shrinking the incredibly ugly sweater he was forced to wear until it no longer fit him and growing all his hair back overnight when the Dursleys had shaved him bald.

* In ''Literature/HarryPotter'', this is how young wizards first manifest their powers prior to learning to control them. In Harry's case for example, his first memory of using magic is [[{{Teleportation}} apparating]] away from some pursuing bullies. Other manifestations include shrinking the incredibly ugly sweater he was forced to wear until it no longer fit him and growing all his hair back overnight when the Dursleys had shaved him bald.

* From the ''TabletopGame/MutantsandMasterminds'' splat book Hero High we get the Holding Back drawback. If enough of your team is disabled or if an appreciable number of innocent lives are at stake (including your own) you switch into an overdrive mode that makes you several levels stronger than you normally are.

** Unlocking the famed [[SuperMode Super Saiyan]] transformation in ''Anime/DragonBallZ'' requires the user to lose all mental and emotional restraint, to get an incredible boost of power. This ''usually'' involves life-or-death stakes and / or a great personal loss.

* Steven from ''WesternAnimation/StevenUniverse'' is full of these: he inherited a lot of powers from his mother and has mastered none of them. He's not aided the the fact that they're even more unreliable than most. His shield has often totally failed to activate in dangerous situations and one time he found himself unable to deactivate it, trapping him and Connie inside for hours.

* The "fight-or-flight" emergency response state makes defence-mechanism "super strength" an occasional TruthInTelevision. When faced with life or death, the human body goes into survival at any cost mode. This includes producing adrenaline which boost muscle strength, shutting down strength restrictions that prevent muscles from tearing themselves apart and releasing endorphins to prevent the sensation of pain. Net result: you can lift a helicopter for several seconds. There is a reason why we can't activate the fight-or-fight reaction voluntarily and can only remain as a Defence Mechanism: The stress response halts or slows down various relaxed processes such as sexual responses and digestive systems to focus all energy on the stressor situation, which means that [[HeroicRROD prolonged stress responses may actually result in long-term bodily damage, like digestive disorders and the suppression of the immune system. If you constantly have your muscles in maximum power due to adrenaline overload, your muscles will eventually tear themselves from the bone, rip themselves apart, or even start to liquefy]]. Of course, the severity of the damage depends on the intensity of the stressor, how far beyond the limits one goes, and for how long.

** Before that, there was Lifeguard, a short-term member of the team whose powers were "whatever's necessary to get people out of harm's way." Under fire? Armored skin. Someone's falling from a building? Sprout wings. And so on. Like Darwin, this doesn't always translate into "beat the bad guy threatening everyone." Worse, if ''she's'' in danger, she's on her own.

* In ''Fanfic/ChildOfTheStorm'', Harry's protection from his mother, [[spoiler: which takes the form of a connection to the Phoenix, combined with DeathActivatedSuperpower]] - whenever he's in mortal danger, [[spoiler: dying or dead, the Phoenix]] protects him, usually fairly subtly (relatively speaking). First by protecting him from Voldemort's killing curse as a baby, then by incinerating Quirrell, the by ensuring that Fawkes came to his aid in the Chamber of Secrets and then by giving his PsychicPowers the nudge they needed to activate and send a distress call, triggering the events of the story, and in chapter 58, [[spoiler: scaring off Hera]]. And then, in chapter 71, subtlety is dispensed with [[spoiler: by resurrecting him, possessing him, and going on a rampage that kills at least a couple of dozen HYDRA Agents and several hundred Dementors.]]

* ''Webcomic/TowerOfGod'': At first, Twenty-Fifth Bam's powers are completely passive, resulting in magic resistance. And occasionally, for example when he and Rachel get curb-stomped by Hwaryun, they are a last defense and use [[FunctionalMagic Shinsu]] to cut up faces. And [[EyeScream eyeballs]].

* ''Manga/JoJosBizarreAdventure'' has a Stand called "[[Music/{{U2}} Achtung Baby]]" (yes, the entire series is [[ShoutOut music references]]). It activates its power of invisibility when its infant user is scared. Of course, in a series where HeartIsAnAwesomePower, this is incredibly useful.

* In ''VideoGame/GoldenSun'', [[PsychicPowers adepts]] have forms of [[ElementalPowers Psyenergy]] which unconsciously protect them when they need it. This is first demonstrated in a cutscene in ''VideoGame/GoldenSun2001'' when [[spoiler: they first enter Kolima or Kolima forest. They discover that some crystals are raining from the sky and turned the villagers into [[AndIMustScream trees]]. They're knocked unconscious but are protected by a shield (which reappears in several other parts of the game to help avert ConvectionSchmonvection and the like)]]. They vow to make an attempt to master this unconscious power, but never actually learn to willingly trigger it.

In video games, this may come in form of a passive ability that activates when you get hit by an attack, or when the enemy's attacking you. Compare CriticalStatusBuff and DesperationAttack, where having low health/getting attacked a lot either gives you a buff or allows you to perform a powerful attack.