-> '''Victor''': Tell me something, Jimmy. Do you even know how to kill me?\\
'''Logan''': I'm gonna cut your goddamned head off. See if that works.
-->-- ''Film/XMenOriginsWolverine''

The intersection of AchillesHeel with OffWithHisHead.

When a character or group is lauded to be immortal, indestructible, or otherwise unkillable, oftentimes one of the few if not the only things they are not immune to is decapitation. This could be a [[TheReveal reveal]], it could be known from the getgo as "the only way to kill them"; or, as in the quote above, it could be in-universe speculation which may or may not get put to the test.

The reason for the prevalence of this trope, particularly of the latter form, probably has its roots in the RuleOfPerception. An audience can swallow a character being [[NighInvulnerability shot full of bullets or losing a gallon of blood and shrugging it off]], [[MadeOfIron even when there isn't a good reason for it]]. And the removal of vital organs, up to and including the heart, is still conceivably survivable because hey, [[HealingFactor they can just grow a new one!]] After all, [[AndShowItToYou one can survive a few seconds with no heart even in real life]], so as long as you can regenerate within that time span you're good, right? But decapitation crosses the line from "should be dy''ing''" to "already dead by definition," and you have ''zero'' time to heal. In the minds of viewers and characters alike, you just can't ''be'' alive if your head is not attached to your neck, and it takes more than a HealingFactor to explain how you can be.

RemovingTheHeadOrDestroyingTheBrain is a specific subtrope for the undead. That said, in general beings who ''are'' "already dead" have a higher chance of averting this trope than those who aren't. Don't even ''bother'' trying this on DemBones, [[CraniumChase unless your aim is]] [[PlayedForLaughs comedy]]. Vampires are an exception, however, as decapitation has long been a stock method of killing them. When this trope doesn't apply to a robot, it's likely because of a CranialProcessingUnit.

When cutting something's head off ''doesn't'' kill it, it's LosingYourHead. See also ChunkySalsaRule and BoomHeadshot.

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!Examples:

[[foldercontrol]]

[[folder:Anime And Manga]]
* In ''LightNovel/TheTwelveKingdoms'' beheading is one of the certain ways to kill an immortal (the others being [[HalfTheManHeUsedToBe cutting the body in two]] and use of special enchanted weapons), and is shown to be the preferred method in executions. In example, this is how [[spoiler: King Chuutatsu, Queen Kekai and the ''kirin'' Hourin]] are killed.
* Subverted with Hidan from ''Manga/{{Naruto}}''. Asuma ''thinks'' it'll work and cuts it off, but all it does it keep Hidan from controlling his body and Kakuzu can re-attach it. [[spoiler:Shikamaru later blows him up to the point where the only part left is his head. Hidan cusses him out. Shikamaru [[AndIMustScream buries the still-living and near-immortal head in a hidden grave where no one can ever retrieve it]].]]
* Averted in ''Anime/NinjaScroll'': Jubei thought Gemma was dead from this, but he reappears with a faint scar around his neck.
* ''Manga/{{Berserk}}'' has Guts fighting a monster that can regenerate as long as its head is intact...[[TooDumbToLive which it brags about to Guts.]]
* ''Manga/MermaidSaga''. Not the only way to kill an immortal, but the most effective and most attempted.
* In ''Manga/MagicalRecordLyricalNanohaForce'', this is one of the only ways you could kill an [[ViralTransformation Infected]]. Anything else will just be [[HealingFactor healed off with ridiculous ease]].
* Most awakened beings in ''Manga/{{Claymore}}'' will die easier if connection between brain and body is removed, generally by decapitation. Semi-averted by one, whose connection ran through her hair and neck was used only as a distraction.
** Abyssal Feeders can regenerate indefinitely, making destruction or removal of the head the only means of stopping them.
* The Immortals in ''Manga/BladeOfTheImmortal''.
[[/folder]]

[[folder:Comic Books]]
* In the French series ''ComicBook/ZornAndDirna'', Death is trappped in a magical mirror, and now every single living creature is fated to [[AgeWithoutYouth age forever]], unless the spinal column is severed, in which case the dead one's soul goes into the killer's. [[AndIMustScream It is specifically mentioned that butchers have adapted by developing the skill of removing meat from an animal without cutting the spine.]]
* In ''ComicBook/{{X-Men}}'', a 90s plotline involved the "Xavier Files", which were basically Professor Xavier's Batman-esque contingency plans for the best way to kill any of the X-Men (including himself) if they turned evil. For {{Wolverine}}, the only sure way to overcome his HealingFactor was said to be decapitating him and quickly removing the head from the vicinity of the body.
* In ''DemonKnights'' a vampire army besieging the protagonists can only be defeated by [[RemovingTheHeadOrDestroyingTheBrain removing the head or destroying the heart]].
* Dracula is vanquished several times in ''Comicbook/TheTombOfDracula'' and ''Comicbook/DraculaLives'', but since his head is never removed afterwards to make his death permanent, he always manages to return.
[[/folder]]

[[folder:Film]]
* In the ''Franchise/{{Highlander}}'' series, beheading is the only thing that will kill an Immortal. The best way to behead an Immortal is with some variety of blade, hence all the {{Sword Fight}}s that Immortals get into in the series. The question of whether this is the ''only'' limit to their immortality is usually glossed over.
* ''Film/TheMummyReturns'': The only way to kill an Anubis Warrior is by cutting off its head.
* In addition to the page quote, ''Film/XMenOriginsWolverine'' uses this [[spoiler:on Weapon XI.]] This is shown in the movie as being the only way to kill anyone with a HealingFactor. [[spoiler: It doesn't work, in this case; TheStinger shows Weapon XI's body crawling over to reattach his head.]]
* Horribly subverted in ''Film/TheThing1982''. Decapitation does absolutely nothing to the Thing. When its head is removed [[LosingYourHead it acts as an independent organism]] and tries to escape.
[[/folder]]

[[folder:Literature]]
* ''Literature/MistbornTheOriginalTrilogy'':
** [[PlayingWithATrope Played with]] with [[BigBad The Lord Ruler]]. He's [[AGodAmI lauded as an immortal god]], and it's common knowledge that "decapitation only irritates him," so nobody ever tries this. It's also [[RasputinianDeath one of the many things he claims to have survived]] in a BadassBoast while fighting the heroes. However, [[spoiler:the source of his agelessness, once revealed, makes one wonder if this was actually true]], and according to WordOfGod [[InvokedTrope it was a big fat lie]]]].
** Decapitation kills the [[ImplacableMan Steel Inquisitors]], who are otherwise almost impossible to beat--although it's usually easier to just pull out the spike in their backs, which also kills them.
* In Creator/BrandonSanderson's earlier work, ''Literature/{{Elantris}}'', Elantrians are most reliably killed by beheading. Anything less will simply leave [[WoundThatWillNotHeal an unhealing, eternally-hurting wound]]. [[KillItWithFire Burning also works.]]
* The short story [[Literature/DragonReserveHomeEight "Dragon Reserve, Home Eight"]] by Creator/DianaWynneJones features "hegs," people with superhuman abilities including being able to "mind read, kindle fire or more objects at a distance, heal or kill by use of mind alone, survive shooting, drowning, or suffocation..." By law, once discovered they are executed by beheading, which is the only thing they cannot survive.
* In the ''Literature/KeysToTheKingdom'' series, beheading can kill a Denizen, but their heads have to be separated from their bodies for some time, or throwing dirt in the neck stump apparently usually works.
* PlayedForLaughs in Creator/TerryPratchett's ''Discworld/CarpeJugulum'', in which vampires from different areas of uberwald have to be dispatched in varying ways (lemon in the mouth, nail through the knee, hide his sock) but all involve cutting off the head (which, conveniently, also works on people).
* The [[StockNessMonster Brollachian]] from ''Literature/ShadowKeep'' is a part ogre part octopus brute that feels no pain and can regenerate missing limbs and chunks of flesh. However, [[TheSmartGuy Maryld]] stated that he can be slain if beheaded, but the heroes never get the chance of trying this on it.
* The only way to successfully kill a vampire in the ''Literature/MercyThompson'' series is to stake them, decapitate them, and then [[KillItWithFire burn both the head and body to ashes]].
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/{{Heroes}}'': It's stated that characters with a HealingFactor can't survive decapitation, although it's never actually shown. The more commonly referenced means of taking one down is by shooting or stabbing [[AchillesHeel a very specific point in their brain]], but that only works temporarily; if the object is removed, they will still heal. Not so, allegedly, for full decapitation.
* On ''Series/{{Supernatural}}'':
** This is how the "unkillable" Leviathans are finally defeated. [[LosingYourHead It still doesn't actually kill them]] but it incapacitates them until their heads crawl back over to their bodies, a problem solved by simply putting the head in a box. It seems that in this case, [[LosingYourHead removing the head doesn't work]], but [[RemovingTheHeadOrDestroyingTheBrain destroying the brain does]].
** This is sometimes the case with run-of-the-mill monsters, depending on species.
* [[SubvertedTrope Subverted]] In ''Series/TorchwoodMiracleDay''. Jack Harkness suggested cutting off the head of an assassin who is being kept alive by the miracle (despite being [[BodyHorror burned to a crisp]]. The authorities try it, '''and he's still alive.''' Jack himself also subverts this in all post 9th doctor appearances except the aforementioned Miracle day.
* "Braining" always worked on ''Series/StarTrekTheOriginalSeries''.
* Decapitation is one of the few ways to kill a vampire in ''Series/{{Buffy|the Vampire Slayer}}''. They instantly turn to dust once their head isn't attached to their body. ''Series/{{Angel}}'' brings up another caveat; vampires have a HealingFactor but their brain won't heal from some injuries, meaning they could be left brain-damaged for all eternity if something happened to it. This is mentioned, but [[InformedAttribute it never comes up in the actual story.]]
** Subverted with Lorne (and presumably other Pyleans); in order to kill one of their kind, you must decapitate them ''and'' dismember the body. Lorne's family saved him (grudgingly) by switching his clothes with that of another decapitated body awaiting dismemberment.
[[/folder]]

[[folder:Mythology and Religion]]
* GreekMythology:
** Averted with the Hydra from GreekMythology. It started off with nine heads, and every time one was cut off it would grow two in its place. Hercules finally defeated it by cutting off its heads and having a friend cauterize the stumps with fire to prevent them from regrowing. However, it had one immortal head; and presumably that was undecapitable. Once the others were destroyed, Hercules just buried that one.
** The weakness of Medusa, the gorgon. While her two sisters were immortal, Medusa had a mortal neck covered in metallic scales which could be severed by means of an adamant blade, which the hero Perseus used to kill her.
[[/folder]]

[[folder:Tabletop Games]]
* Subverted in ''[[TabletopGame/DungeonsAndDragons DnD]]''; Vorpal weapons instantly decapitate enemies on a critical hit, but some enemies either don't have heads to remove, or aren't inconvenienced by it. Specifically, the latter includes monsters with regeneration (though Ogre Mages need to reattach their heads within ten minutes), most Constructs, and Undead (save for vampires).
* ''TableTopGame/{{Pathfinder}}'' has Vorpal weapons that are much likes the ones in DungeonsAndDragons. In addition, ''Pathfinder'' also introduces the [[Literature/AliceInWonderland Jabberwock]] creature, which has a particular fear of vorpal weapons; striking one cause it to become temporarily shaken.
* Decapitating a Harrowed from ''TabletopGame/{{Deadlands}}'' doesn't kill them. [[FateWorseThanDeath It reduces them to fully conscious but helpless heads]].
* In the French RPG ''TabletopGame/{{Trinites}}'' it is usually the surest ways to kill the eponymous beings for good.
[[/folder]]

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