Remove the Head or Destroy the Brain

A trope commonly associated with zombies and mummies, as well as other forms of undead - to put down the creature for good, or else render it far more vulnerable, you usually have to Remove the Head or Destroy the Brain. The head and brain are logical targets for disabling or killing an enemy, be they living or otherwise - after all, they're basically the cockpit a majority of living thing pilot their meat suit of a body from. The trope also applies to some living and nonliving beings as well - many Humanoid Aliens and constructs that are especially durable may operate on similar logic, which only makes sense.

But what makes this subtrope of Attack Its Weak Point different from other examples - and what makes it more than just Losing Your Head - is the implication that nothing else will do the job: Take off a zombie's legs and it'll drag itself after you; take off the arms, and it'll still try to worm its way towards you. Even dismemberment may not cut it completely - as long as the head's still around, that undead monster will still be moaning and groaning as it hops or rolls in your general direction, and it may or may not be joined by the rest of its body parts... but once you pulp that noggin, its remains will promptly go inert and wither away. Hopefully...

Of course, beings undead and otherwise can also subvert this as well; Skeletons are common candidates among the undead both for subverting and playing this straight, and whether robots are still able to function on some level without their head attached depends on who's writing. There's also plenty of Non-Human Undead and other similar Hybrid Monsters to contend with - and not every such creature will even have their brain in their head, after all.

Using this to dispatch Multiple Head Cases has varying results, depending on how much the heads control the body. Some are sufficiently disabled with the removal of one head, while more persistent types may require the removal of all of them - and then there's the potential for a Hydra Problem...

One way to make such a kill stick is to make the head explode and/or land a choice headshot. Successfully doing this can render someone Deader Than Dead.

Anime and Manga

 * While the Namekians of the Dragon Ball series can be killed like any other being, they possess a highly potent regeneration factor that lets them regrow lost limbs; Piccolo in particular states during the Buu Saga that he can regenerate from nearly anything as long as his head isn't damaged, which presumably applies to the rest of his people.
 * The cores of the Angels in Neon Genesis Evangelion may not function neurologically as brains, but are effectively so for the purposes of this trope -- until the core is destroyed, an Angel has effectively unlimited regeneration and can come back from almost any damage.

Film

 * Avengers: Infinity War:
 * The only way to kill an Immortal in the Highlander film and TV franchise is to remove their head.
 * The only way to kill an Immortal in the Highlander film and TV franchise is to remove their head.

Literature

 * The titular Jabberwocky is dispatched this way in Lewis Carroll's poem; both the creature and the weapon that slew it have been referenced by many works and games since.

Live-Action TV

 * Some species of demon in Buffy the Vampire Slayer can only be killed by removing their heads. (And a few are completely unbothered by such a trivial injury.)

Oral Tradition, Folklore, Myths and Legends

 * Classical Mythology:
 * In most versions of Medusa's story, Perseus was explicitly sent to fetch her head by King Polydectes of Seriphus, who expected him to die in the process so that he could forcibly marry his mother. However, Perseus would succeed with the help of the gods' gifts in dispatching her by using winged sandals to avoid detection, then using his reflective shield to view her safely and guide his sword; he then collected her head in a special sack. Since she was pregnant at the time due to Poseidon, her decapitation produced the winged horse Pegasus and the golden sword-wielding giant Chrysaor, father of Geryon.
 * Perseus would then show the head to Polydectes - turning him and his attendant nobles to stone - before he presented it to Athena, who placed it on her aegis. Ovid's telling of the story suggests that he made use of it en route, turning the Titan Atlas to stone as he tried to attack. Ovid and some other tellers also suggested that drops of blood from the decapitated head created the corals of the Red Sea, the poisonous vipers of the Sahara, and the dragon-like, snake-head-tailed Amphisbaena.
 * The Lernaean Hydra (she of problematic fame) was killed this way as part of the Labors of Heracles. The Hydra was immortal as long as one head remained, and for every one head that was removed, two more grew back in its place - Heracles circumvented this with the helps of his nehpew Iolaus, using either a firebrand or the Hydra's own potent venom to sear the neck stumps and prevent them growing back. The Hydra's one immortal head was then cut off with a golden sword gifted from Athena and buried under a stone.

Video Games

 * Fallout New Vegas has an interesting variation of this trope. While practically anything can die if their head is destroyed, the Ghost People of the Dead Money DLC are a special case While they die (by game engine standards) if any limb is blown off, they still breathe and are alive to some extent, according to the unique mutation they have - unless their head is explicitly destroyed, which prevents them from breathing and thus keeping their bodies in motion.
 * The Legend of Zelda has many a creature that can only be thwarted with the removal of its head, including several skeletal enemies (whose names usually include the prefix "Stal-"):
 * Zelda II: The Adventure of Link has the Geldarm, large centipede-like insects that block Link's path in desert levels; the player must attack their body, then strike at the head a few times as they lower to Link's height to defeat them.
 * Big Babas in Twilight Princess are carnivorous plants that share symbiotic relationships with Deku Likes, acting as the head to their body; the latter can only be defeated by first killing the Big Baba, which allows the player to plant a bomb inside the Deku Like.
 * The Stalfos of The Wind Waker will crumble if struck enough times, leaving their head to hop around until their body either regenerates or the player hits it enough times; smashing their head with the Skull Hammer will defeat them instantly. Stalfos Knights in Cadence of Hyrule function similarly, though destroying the body's remains after collapsing them also works. This also applies to Stalchampion from Tri Force Heroes, who is reduced to a disembodied skull during its final phase.
 * Nethack:
 * The Vorpal Blade of Jabberwocky fame has a 5% chance to behead the victim upon hitting them, unless they have no head or else are intangible (e.g. ghosts, shades and vortices) which causes that strike to miss completely. This even includes nonliving monsters and multiheaded monsters such as ettins - of course, this also applies to you if you're caught on the wrong end, which is a very likely danger if you haven't generated it yet. And yes, it always works against jabberwocks.
 * While possibly not literal, brainlessness can result from being hit with one too many brain-eating attacks by a mind flayer, which reduces your intelligence - not only is this also an instadeath if your INT drops too low, but even won't work properly, since your brain will still be gone after.
 * In Nethack variants:
 * The vorpal jabberwock is a deferred monster in the vanilla game based on the jabberwock; variants that include it, such as GruntHack and UnNetHack, often give the monster its own beheading attacks, though it retains the weakness to Vorpal Blade.
 * SLASH'EM introduces Thiefbane, a chaotic-aligned long sword that has a 10% chance to behead any human or elf (specifically ) that it hits. The Verbal Blade, the Zyborg quest artifact, is also capable of beheading monsters.
 * In many variants of NetHack that use the "object properties" feature, "vorpal" is a property that gives an object with it the same chance to behead monsters as the original Vorpal Blade.
 * dNetHack in particular introduces many artifact weapons capable of beheading. Snickersnee, the first guaranteed sacrifice gift for Samurai, is now an intelligent knife that has a chance of beheading targets. Samurai can also name The Kusanagi no Tsurugi, which is only possible at level 18 and only actually usable once you hit the Level Cap of 30; this Tsurugi is an intelligent long sword that can behead targets in addition to providing many other perks.
 * God of War series:
 * Various types of Cerberus appear as enemies and bosses throughout the series that Kratos usually kills by beheading, one head at a time.
 * As a downplayed example, some of the serpentine Gorgons can be beheaded as a specialized finisher in some of the various games. In God of War: Ghost of Sparta, Kratos's finisher strangles them and causes their heads to explode, releasing petrification energy that turns all enemies in the room to stone; in God of War III, he uses their freshly-liberated heads to do the same; and in God of War: Ascension, their heads are cut in half, releasing the petrifying magic on all enemies in the room. Medusa in the first game and Euryale in the second are dispatched this way, with their heads acting as usable items that can turn enemies to stone.
 * The first game has the multi-headed Hydra as the boss of the Opening Action Sequence, which doubles as a Tutorial Level. Kratos is shipbound during the fight, and solves this Hydra problem (no, not that one) by taking out the Hydra King - the "main" head that heals and revives the others - using the ship's main mast to impale it repeatedly through the roof of its mouth.
 * In Ghost of Sparta, Kratos uses a giant Archimedean Screw to drill through the head of and finish her off.
 * In the second game, Kratos kills Clotho,, by driving a blade through her skull. He also uses this trope to kill Theseus, smashing his head in with the door he was guarding, and Alrik, whose head he beat in with his own hammer, after
 * In the third game, the "honor" of having their head become a weapon would go to Helios, whose head Kratos pulls straight off his body - he can then use the head to blind and stun enemies, illuminate dark areas and uncover secrets.
 * Kratos also disposes of by driving the Blade of Olympus through his forehead.
 * In the 2018 game,
 * Also in the PS4 entry is Brok, who boasts of subverting doing this to himself as a child.

Western Animation

 * In the final season of Samurai Jack, Scaramouche manages to survive his defeat at Jack's hands as a head, and just barely manages to make it back to his master Aku in time with news that the samurai had lost his sword, which was enough to earn Scaramouche his body back. Unfortunately for him, by the time they next encounter Jack, he's long recovered his sword - Aku's punishment is... rather apt.

Real Life

 * Cockroaches are subject to popular claims of being able to live without their heads, potentially subverting this trope; however, their capacity for such is exaggerated, and the trait is by no means exclusive to them. That said, a cockroach's severed head can still survive and wave its antennae for several hours, while the body still demonstrates behaviors such as shock avoidance and escape behavior.