History Main / KryptoniteFactor

** ''Film/BatmanVSupermanDawnOfJustice'' has Kryptonite discoved among the wreckage of the [[DoomsdayDevice Kryptonian World Engine]] near India after the events of ''Man of Steel''. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. [[AdaptationalWimp In contrast to most portrayals, a small amount has no effect just in proximity.]] [[spoiler:Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a FinishingMove.]] This also applies to [[spoiler:Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.]]

* ''Series/{{Riverdale}}'': When Archie became NighInvulnerable in Season 6, he finds out he loses his powers when he's arround palladium and asks Betty to keep it away from him. This, of course, is used against him by the season's BigBad. [[spoiler:He later overcomes this weakness when Cheryl forged his skin to be impervious to palladium, but in the process he gains a new weakness: the daggers of Migido.]]

** ''Film/BatmanVSupermanDawnOfJustice'' has Kryptonite discoved among the wreckage of the [[DoomsdayDevice Kryptonian World Engine]] near India after the events of ''Man of Steel''. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. [[AdaptationalWimp In contrast to most portrayals, a small amount has no effect just in proximity.]] [[spoilers:Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a FinishingMove.]] This also applies to [[spoiler:Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.]]
* In ''Film/DraculaUntold'', vampires have the standard array of weaknesses: silver, sunlight, wooden stakes, and crosses. Also played with a bit. Crosses only work on permanent vampires, the ones that have fed on humans. Those like Vlad, who will turn back in three days, are unaffected. Stakes, on the other hand, are not only effective but ridiculously so; when Mehmet goes after Vlad with a stake, his armor actually evaporates around it so the stake will hit flesh.e

** ''Film/BatmanVSuperman:DawnOfJustice'' has Kryptonite discoved among the wreckage of the [[DoomsdayDevice Kryptonian World Engine]] near India after the events of ''Man of Steel''. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. [[AdaptationalWimp In contrast to most portrayals, a small amount has no effect just in proximity.]] [[spoilers:Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a FinishingMove.]] This also applies to [[spoiler:Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.]]

** In ''Film/BatmanVersusSuperman:DawnOfJustice'', Kryptonite is discoved among the wreckage of the [[DoomsdayDevice Kryptonian World Engine]] near India after the events of ''Man of Steel''. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. [[AdaptationalWimp In contrast to most portrayals, a small amount has no effect just in proximity.]] [[spoilers:Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a FinishingMove.]] This also applies to [[spoiler:Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.]]

** In ''Film/BatmanVersusSupermanDawnOfJustice'', Kryptonite is discoved among the wreckage of the [[DoomsdayDevice Kryptonian World Engine]] near India after the events of ''Man of Steel''. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. [[AdaptationalWimp In contrast to most portrayals, a small amount has no effect just in proximity.]] [[spoilers:Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a FinishingMove.]] This also applies to [[spoiler:Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.]]

* Lampshaded in ''Film/{{Unbreakable}}''. David is a horrible swimmer and nearly drowned once as a kid. Discovering this was evidence reinforcing that he ''was'' actually "unbreakable" because all heroes have some sort of weakness. Another character points it out to him, saying "that's your Kryptonite."
* In ''Film/{{Highlander}}'' all of the Immortal characters are just that; they are able to shrug off almost any wound, they're immune to all forms of disease, do not age a day in their life and are even capable of surviving without oxygen. The only proven method for defeating them is [[OffWithHisHead decapitation]].

* In ''Film/WhoFramedRogerRabbit'', Toons are invulnerable to conventional damage, but can be injured or killed by a specific blend of paint-and-ink-thinning chemicals, known as "the Dip". Immersion is fatal, and a Toon cab who'd skidded through a puddle of Dip suffered four flat tires and was left limping in pain. They also can't let the ol' "ShaveAndAHaircut - Two Bits" go unfinished. Roger ends up ruining their hiding spot because of it.

* Lampooned in-character in ''Film/TheAmazingSpiderMan'', when Spider-Man responds to a crook pulling a knife by [[LargeHam melodramatically pretending to collapse]] and gasping "You've discovered my weakness... small knives!".
* ''Film/ManOfSteel'':
** Exposure to Krypton's native environmental conditions weaken and at first even incapacitate Superman.
** Zod's Kryptonians similarly initially lose control of their powers and pass out while trying to adapt to Earth's native atmosphere.
* ''Film/XMenApocalypse'': Nightcrawler's teleportation power is blocked by electrical fields. They also interfere with Jean Grey's telekinesis and telepathy.
* In ''Film/LemonadeJoe'', Joe is a strong, tough guy with ImprobableAimingSkills. There is one substance that is his Achilles Heel and makes him lose consciousness, leaving him at his enemies' mercy. It's alcohol.
* In ''Film/DraculaUntold'', vampires have the standard array of weaknesses: silver, sunlight, wooden stakes, and crosses. Also played with a bit. Crosses only work on permanent vampires, the ones that have fed on humans. Those like Vlad, who will turn back in three days, are unaffected. Stakes, on the other hand, are not only effective but ridiculously so; when Mehmet goes after Vlad with a stake, his armor actually evaporates around it so the stake will hit flesh.
* The Dragon spell from the [=PLATO=] computers ''VideoGame/{{dnd}}'' game has no effect on normal enemies, but it instantly kills the dragon FinalBoss.

* Haar in ''VideoGame/FireEmblemRadiantDawn'' is an otherwise OneManArmy mechanically, but (also mechanically) is always 2 hit killed by thunder mages.

** The Doctor's [[MagicTool sonic screwdriver]] was notorious for having no specific guidelines or limits to how it could be used, so much that lazier writers would rely on it too much as a DeusExMachina to get the Doctor out of any predicament. The Fifth Doctor broke it in the Season 19 episode "[[Recap/DoctorWhoS19E4TheVisitation The Visitation]]" and went without it for the rest of the Classic series. When the series [[{{Revival}} returned]] in 2005, two very specific limitations were put on it: a), the screwdriver can't break through [[TechnoBabble a Deadlock Seal]], and b), "[[WeaksauceWeakness it doesn't do wood]]". The latter has been repeatedly {{lampshade|Hanging}}d as "rubbish".

** The Doctor's sonic screwdriver was notorious for having no specific guidelines or limits to how it could be used, so much that lazier writers would rely on it too much as a DeusExMachina to get the Doctor out of any predicament. The Fifth Doctor broke it in the Season 19 episode "[[Recap/DoctorWhoS19E4TheVisitation The Visitation]]" and went without it for the rest of the Classic series. When the series [[{{Revival}} returned]] in 2005, two very specific limitations were put on it: a), the screwdriver can't break through [[TechnoBabble a Deadlock Seal]], and b), "[[WeaksauceWeakness it doesn't do wood]]". The latter has been repeatedly {{lampshade|Hanging}}d as "rubbish".

** The Doctor's sonic screwdriver was notorious for having no specific guidelines or limits to how it could be used, so much that lazier writers would rely on it too much as a DeusExMachina to get the Doctor out of any predicament. The Fifth Doctor broke it in the Season 19 episode "[[Recap/DoctorWhoS19E4TheVisitation The Visitation]]" and went hands-free for the rest of the Classic series. When the series [[{{Revival}} returned]] in 2005, two very specific limitations were put on it: a), the screwdriver can't break through [[TechnoBabble a Deadlock Seal]], and b), "[[WeaksauceWeakness it doesn't do wood]]". The latter has been repeatedly {{lampshade|Hanging}}d as "rubbish".

** The Doctor's sonic screwdriver was notorious for having no specific guidelines or limits to how it could be used, so much that lazier writers would rely on it too much as a DeusExMachina to get the Doctor out of any predicament. The Fifth Doctor broke it and went hands free. When the series returned in 2005, two very specific limitations were put on it: a), the screwdriver can't break through [[TechnoBabble a Deadlock Seal]], and b), [[WeaksauceWeakness "it doesn't do wood"]]. The latter has been repeatedly {{lampshade|Hanging}}d as "rubbish".
** [[Recap/DoctorWhoS28E2ToothAndClaw "Tooth and Claw"]]: The werewolf is allergic to mistletoe. The Doctor suggests that the monks who worship it may have conditioned this weakness into it, and at any rate the monks wear garlands of it to prevent it from getting any ideas. Likewise, Sir Robert's late father covered the library's walls and doors with mistletoe oil, keeping the wolf at bay for a while.

** Ooze [[KillItWithFire can only be killed with fire]]

* ''Manga/CallOfTheNight'': While it is unclear exactly how much sunlight weakens vampires, all of them have an inescapable weakness in the form of an object from their days as humans to which they have a strong emotional attachment (such as a present to/from a loved one, or something to remember them by). Physically touching said object will paralyze the vampire and nullify their HealingFactor, leaving them vulnerable. In some cases, prolonged physical contact can even drive them into a frenzy. [[spoiler:Being a {{dhampyr}}, Nazuna is initially assumed to have no such weakness since she was never human... until Kiku finds one in the form of her umbilical cord.]]

The Kryptonite Factor is an AchillesHeel, where the weakness is a substance or state that only affects the {{Superhero}}. It serves a few purposes.

The artistic one is to show that no one is [[InvincibleHero invulnerable]], not even our [[SuperpowerLottery godlike main character]]. This is especially ironic if the vulnerability is [[WeaksauceWeakness completely arbitrary and commonplace]].

The more powerful a character is, the more likely the Kryptonite Factor will be abused. Writers in particular tend to dislike immensely powerful characters with a single Kryptonite Factor, because not using it creates a [[DramaPreservingHandicap drama-destroying]] sense that the character is never under a serious threat. Conversely, working a rare Kryptonite Factor into the plot repeatedly can [[KryptoniteIsEverywhere seem even more contrived]].

The most obvious example is kryptonite, the bane of ComicBook/{{Superman}} regardless of [[StrongAsTheyNeedToBe how powerful he is being portrayed at the time]]. A literal {{green rock|s}}, it seemed unusually abundant in supervillainous hands for being radioactive bits of a planet that exploded lightyears away. Many {{Elseworld}}s and spin offs to the ''Superman'' mythos include characters who are more resistant to kryptonite, but conveniently, not as strong.

Thanks to ''ComicBook/{{Superman}}'' being a {{Long Runner|s}}, and PopCulturalOsmosis, a common bit of MemeticMutation is to refer to something you are particularly vulnerable to as "My Kryptonite".

Not to be confused with ''Series/TheKryptonFactor''. Contrast LogicalWeakness, wherein the weakness logically comes about as a direct result of the powers. ByThePowerOfGrayskull is more or less the opposite, giving powers as opposed to taking them away.

* Franchise/SpiderMan would occasionally make sly references to a "guy who's allergic to green rocks".

** Anyone who has eaten a Devil Fruit has two, related Kryptonite Factors: The ocean, which causes power leeching and an inability to move due to weakness, and Seastone, also known as ''Kairouseki'' or as "Sea Prism Stone", which replicates the effects of the ocean and out of which most prisons in the ''One Piece'' world are built.

* In ''Anime/FullmetalAlchemist2003'', the homunculi become vulnerable when [[spoiler:they come into close proximity to the body of the human of whom they are a ShadowArchetype]].

* ''Literature/{{Anpanman}}'': The titular hero has a head made of bread, which is his weak point. If he breaks off too many pieces of it to feed others, or his head gets wet, dirty, bruised up, or moldy, he loses his power. Once a new head is put on, he gains all the energy he needs again.
* ''Literature/ACertainMagicalIndex'': Saints are people {{born|Winner}} with physically perfect bodies similar to the Son of God. This gives them great powers like incredible levels of SuperStrength, SuperSpeed, SuperToughness, etc. However, they are vulnerable to any of the tools that were used to torture Jesus. For example, if an ordinary person punched them or hit them with a baseball bat, they could easily shrug it off. But if a Saint was hit with a cross, crown of thorns, scourging whip, etc, the item would hurt them like it would a normal person. There are also spells designed to combat Saints, like the appropriately named "Saint Destroyer".
* ''Manga/AssassinationClassroom'': Revealed very early on is a rubbery material that, to humans, is about as damaging as actual rubber, while messily popping Koro-Sensei's flesh even on quick contact, and being able to kill him off if it strikes near his heart. However, this doesn't help much; you still need to make contact with it, which is easier said than done when fighting someone with a Mach 20 FlashStep.
* ''Literature/BlackBullet'': The monsters known as Gastrea are practically invulnerable to normal weapons, but weapons and bullets made of the metal Varanium can harm them, and monoliths made of Varanium can drive them away. However, there are Gastrea that are powerful enough to ignore the monoliths. Due to FantasticRacism in the series, it's been also used against [[WoobieSpecies cursed children]] who are born with the virus. [[spoiler:A group of cursed children that Rentaro taught were killed by a bomb filled with Varanium shards.]]
* ''Manga/DontMeddleWithMyDaughter'':
** Athena and her daughter, Clara, are a parody of ComicBook/PowerGirl and ComicBook/{{Supergirl}} respectively and have the same [[FlyingBrick basic set of powers.]] Their weakness...? It's [[DefeatByModesty sexual harassment.]] In their setting, virtually everyone is a pervert from the villains, to the bystanders they put themselves at risk to protect.
** For Athena in particular, the constant [[LustObject shame and degradation]] she had to endure forced her to retire 20 years prior to the start of the series. But after learning her daughter had taken up her mantle, Athena dons her cape again to protect Clara, from the shadows.
* ''Manga/KnightsOfSidonia'': The alien Gauna can only be killed by a peculiar metal substance called "kabi". Even such things as planet-buster warheads will do nothing to a Gauna's core, and it will regenerate all damage, but so much as touch the core with kabi and the whole thing falls apart permanently. The ''Sidonia'' ran across a giant, seemingly artificial but abandoned structure made of the stuff and harvested what they could before a Gauna attack forced them to move on. They have to be very careful with the couple dozen spears they made out of it because they don't have a clue how to manufacture it nor where more can be found.
* ''Manga/MakenKi'': For most of the world, [[BigBad Yamato Takeru]] is a seemingly unstoppable force of evil. Made moreso, since [[YouCantKillWhatsAlreadyDead he's already dead]], has near godlike combat prowess, and has numerous clone bodies to inhabit. The only thing that can hurt him is [[LightEmUp "White Element"]], which is so rare, that there are only four known ability users in the world that can use it. The protagonist, Takeru Oyama, happens to be one of them.
* ''Anime/KotetsuJeeg'': The titular mecha is weakened when making contact with electricity as it affects the magnetic power that binds his body together. Episode 5 also reveals that strong magnetic storms like solar flares prevent him from combining (at least until they made a special coating spray).
* In ''Manga/BioMeatNectar'', B-M go dormant in direct sunlight. (Only direct sunlight, though, so if it's overcast you're in trouble.) They also tend not to react well to flames, enough that [[AerosolFlamethrower hairspray and a lighter]] makes an effective tool against singular B-M. There are high-tech experimental weapons that break them down at a genetic level, but they're rather rare, delicate and have a short battery life.
* ''Manga/MarryGrave'': The only way to actually hurt Sawyer is to attack Rosalie's body, any wound done to her corpse will appear on Sawyer too.
* ''Anime/{{Ingress}}'': XM fields and Portals impair or outright cancel the abilities of opposite-aligned Sensitives (ej, Jack of the Resistance cannot use his future-sight power while inside an Enlightened field). In some cases it may even prove debilitating/mentally taxing to Sensitives, although this is never shown in the anime. Now consider that XM is everywhere and that anyone with the Ingress app can do something about the fields and Portals.

The Kryptonite Factor is an AchillesHeel, where the weakness is a substance or state that only affects the SuperHero. It serves a few purposes.

The artistic one is to show that no one is [[InvincibleHero invulnerable]], not even our [[SuperpowerLottery godlike main character]]. This is especially ironic if the vulnerability is [[WeaksauceWeakness completely arbitrary and commonplace.]]

The most obvious example is kryptonite, the bane of Superman regardless of how powerful he is being portrayed at the time. A literal [[GreenRocks green rock]], it seemed unusually abundant in supervillainous hands for being radioactive bits of a planet that exploded lightyears away. Many {{Elseworld}}s and spin offs to the Superman mythos include characters who are more resistant to kryptonite, but conveniently, not as strong.

Compare SupernaturalRepellent, which is not specific to superheroes. See also KryptoniteRing, KryptoniteProofSuit and FightOffTheKryptonite. Contrast {{Depower}}, CrossMeltingAura and DramaPreservingHandicap. Related to WhyDidItHaveToBeSnakes If the character is vulnerable to something comparatively mundane (and even non-threatening), that makes it a WeaksauceWeakness. When this trope turns up far more often than seems probable, see KryptoniteIsEverywhere. When this extends to having characters whose powers are nothing more than a Kryptonite Factor, you have a ManOfKryptonite.

Thanks to Franchise/{{Superman}} being a {{Long Runner|s}}, and PopCulturalOsmosis, a common bit of MemeticMutation is to refer to something you are particularly vulnerable to as "My Kryptonite."

* ''Literature/{{Goosebumps}}'': In original series #25 (''Attack of the Mutant''), main character Skipper Matthews defeats the titular Masked Mutant by claiming to be a superhero whose only weakness is sulphuric acid. The Mutant, a shapeshifter who can turn into anything solid by rearranging his molecules, promptly turns into a wave of acid... which is a ''liquid'', and so he can't turn back into his normal self anymore.

** Heroes actually abused this, by having Martian Manhunter pretend to be Superman in front of Lex Luther to get a confession for a crime.

* In an episode of ''WesternAnimation/TinyToonAdventures'' spoofing the ''Franchise/{{Superman}}'' movies, "Super-Babs" was weak to carrot cake -- she couldn't stop eating it, and the villain continued feeding it to her until she was too overweight to fly after him.

** Smoker also has some Kairouseki on the end of his jotte, despite his being a fruit user himself (the weapon is long enough to keep him from coming into direct contact with the stone).
** Often applies with individual Devil Fruit through ElementalRockPaperScissors, particularly Logia. As an example, the fact that Luffy is a RubberMan allowed him to break the normal SortingAlgorithmOfEvil by easily defeating [[PsychoElectro Enel]], whose electric power was like unto a PhysicalGod.

** Busoushoku Haki (Armament Haki) allows the person who use it to surround themselves with a thin but powerful armor (it's mostly invisible until the TimeSkip), allowing the user to negate devil fruit powers by contact. It does not cancel the Devil Fruit power itself, but it's one of the few methods of attacking and hurting Logia-type users. Trained Haki users can use their Busoushoku Haki for their projectile weapons or Devil Fruit powers. And if the Logia-type user has their own Busoushoku Haki, the attacker's Busoushoku has to be stronger in order to bypass their intangibility. A sufficiently advanced Haki user can even resist a Devil Fruit user's powers, though they are still unable to cancel it entirely.

** The effect of Seastone and the sea itself varies from user to user: Luffy (a paramecia user) and Chopper (a zoan user) have severe and painful reactions to either but are still made of rubber (which is used to save his life when he's drowning in the ocean) and a human-zoan respectively while logia fruit users and other paramecia users are simply unable to use their powers

** Anyone who has eaten a Devil Fruit has two, related Kryponite Factors: The ocean, which causes power leeching and an inability to move due to weakness, and Seastone, also known as ''Kairouseki'' or as "Sea Prism Stone", which replicates the effects of the ocean and out of which most prisons in the ''One Piece'' world are built.

* In an episode of ''WesternAnimation/TinyToonAdventures'' spoofing the ''Film/{{Superman}}'' movies, "Super-Babs" was weak to carrot cake -- she couldn't stop eating it, and the villain continued feeding it to her until she was too overweight to fly after him.

* ''LightNovel/ACertainMagicalIndex'': Saints are people {{born|Winner}} with physically perfect bodies similar to the Son of God. This gives them great powers like incredible levels of SuperStrength, SuperSpeed, SuperToughness, etc. However, they are vulnerable to any of the tools that were used to torture Jesus. For example, if an ordinary person punched them or hit them with a baseball bat, they could easily shrug it off. But if a Saint was hit with a cross, crown of thorns, scourging whip, etc, the item would hurt them like it would a normal person. There are also spells designed to combat Saints, like the appropriately named "Saint Destroyer".

* ''LightNovel/BlackBullet'': The monsters known as Gastrea are practically invulnerable to normal weapons, but weapons and bullets made of the metal Varanium can harm them, and monoliths made of Varanium can drive them away. However, there are Gastrea that are powerful enough to ignore the monoliths. Due to FantasticRacism in the series, it's been also used against [[WoobieSpecies cursed children]] who are born with the virus. [[spoiler:A group of cursed children that Rentaro taught were killed by a bomb filled with Varanium shards.]]

** Busoushoku Haki (Armament Haki) allows the person who use it to surround themselves with a thin but powerful armor (it's mostly invisible until the TimeSkip), allowing the user to negate devil fruit powers by contact. It does not cancel the Devil Fruit power itself, but it's one of the few methods of attacking and hurting Logia-type users. Trained Haki users can use their Busoushoku Haki for their projectile weapons or Devil Fruit powers. And if the Logia-type user has their own Busoushoku Haki, the attacker's Busoushoku has to be stronger in order to bypass their intangibility.