[[quoteright:350:[[VisualNovel/{{Snatcher}} http://static.tvtropes.org/pmwiki/pub/images/TSP.gif]]]]
So you're a plucky highly advanced cyborg, and you want to bring about the downfall of humanity through propagation of your own kind. Good for you!

Unfortunately, there's a problem. [[DemonicPossession Because you're a physical being,]] you can't [[BodySnatcher flat-out possess someone]]. Even if you can [[VoluntaryShapeShifting shape-shift]] into a perfect replica of a human, you can't just integrate yourself into normal human society, [[UndeadTaxExemption without any form of identity.]] Sooner or later you'll get the cops on your tail, and all ''they'' need to do is put you through a metal detector and it's Game Over. Even perfectly imitating a real individual will cause problems [[SpotTheImposter if the original]] [[BecauseImJonesy shows up]].

Then you see a GenreBlind InnocentBystander mooking his way down an alley. Hmm.

The InnocentBystander's family [[GlamourFailure doesn't notice anything.]] Why should they? He's [[VillainsBlendInBetter the same as he always was.]] As long as they don't check the one dumpster where you left his skinless corpse and his removed, [[ExpositionBeam scanned-for-memories brain]], you're safe. In all your plucky advanced [[HollywoodCyborg cyborg]] glory.

See also DeadPersonImpersonation and YouAreWhoYouEat.
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!!Examples:

[[foldercontrol]]

[[folder: Anime and Manga ]]

* How the Akuma of ''Manga/DGrayMan'' gain their human forms. To add to the horror of it, though, the body they use is always the one who called the soul powering the Akuma back from the dead -- which only works if they are someone the deceased cared strongly for. So the traumatised soul ends up in a robot body wearing their beloved's skin and with no free will of their own. NightmareFuel much?
* Etzali of ''LightNovel/ACertainMagicalIndex'' has a spell that allows him to do this. He actually only needs about 10 square cm of the target's skin for it to work, but he usually kills them to prevent complications later on. He also states that he usually shadows his target for a while to get a handle on their habits so he can convincingly act like them.

[[/folder]]

[[folder: Comic Books ]]

* The Archaeologists in ''RequiemChevalierVampire'' are resurrected with no skin and have to spend most of their time floating in tanks; when one of them needs to venture outside their servants promptly flay some poor schmuck alive (with lots of screaming and thankfully some discretion shots) so the master can wear their skin.
* In ''RomSpaceknight,'' Dire Wraiths don't ''have'' to kill the people they replace, but they prefer to for obvious reasons. Their preferred method is to [[NightmareFuel drill their tongue into the victim's brain to absorb his memories.]]

[[/folder]]

[[folder: Film ]]

* ''Franchise/{{Terminator}}'':
** The T-1000 from ''Film/Terminator2JudgmentDay'' kills its victims and mimics their appearance.
** Also happened with the Terminatrix of ''Film/Terminator3RiseOfTheMachines''. The current Arnie even lampshades it.
** ''Film/TerminatorSalvation'' has Skynet use BrainUploading and the tech used to build the Arnies to resurrect Marcus. He's essentially a cloned and genetically modified human brain, heart and skin over a termie endoskeleton. So it's not that he's a cyborg with artificial limbs, but a robot with artificial flesh. Yikes.
* If ''InvasionOfTheBodySnatchers'' fits anywhere, it's here.
* The Edgar-Bug in the first ''Film/MenInBlack'' movie skinned and wore an "Edgar Suit" that rapidly decomposed throughout the movie.
* [[QuirkyMinibossSquad Quirky Miniboss]] Cobalt Claw does this to an OfficeLady AlphaBitch in the ''CuteyHoney'' [[TheMovie live-action movie]]. She then proceeds to wear the "suit" backwards while [[CeilingCling crawling on the ceiling]], so apparently it was just ForTheEvulz.
* It's implied in the ''Film/{{Transformers}}'' films that the Decepticons made a point of destroying the vehicles they mimic, partially for infiltration reasons (Blackout caused a great deal of confusion by being a helicopter that was previously destroyed) and partially because they have no regard for human life. The Autobots are, unsurprisingly, more discrete about acquiring their vehicle modes.
** Which leads to FridgeHorror when one considers 'Alice', the Pretender - whose alt mode was a human woman.
* Invoked in the 1988 comedy ''Big Business'' when the twins meet after being SwitchedAtBirth.

[[/folder]]

[[folder: Folklore and Mythology ]]

* OlderThanPrint: TheFairFolk were said to operate this way in English folklore, kidnapping babies and replacing them with lookalikes of their own kind known as "changelings".
* Foxes do this too in Eastern mythology:
** In Korean mythology, accounts vary, but typically the fox finds someone with the right skull dimensions, kills them, eats them, and then puts on their skull and assumes their identity. How long they do this depends on the purpose; maybe just long enough to get into the house and eat your baby, maybe longer.
** Japanese foxes are considerably less AlwaysChaoticEvil, and much less likely to need your skull to impersonate you, but their doing so can still have negative effects on the impersonatee. (Skull size is a factor for them in matters of possession, mostly.)

[[/folder]]

[[folder: Literature ]]

* In ''Literature/{{War of the Dreaming}}'', selkies refer to the skins as "jackets," and they can be made from any species' flesh. Weirdly enough, this is also played for comedy: high-ranking selkie switch skins so often the lower ranks are perpetually confused about their identities.
* In ''Literature/JohnDiesAtTheEnd'', Korrok's clones kill/replace the originals and proceed to go about their lives with all the memories of the original. For added authenticity, although the clones can be remote-controlled in emergencies, the replacements themselves lack alien memories and have no idea they're not the originals. This eventually leads [[spoiler:to a TomatoInTheMirror situation.]]
* The premise of ''Film/{{Impostor}}'' is that look-alike copies of key people can be sent after targets, exploding violently once contact is made. The hero is accused of being one such impostor.
* ''Literature/CodexAlera'''s "watercrafting" can be used to imitate the appearances of others. This leads to a shock for one of our protagonists; [[spoiler:Tavi discovered that his friend Gaele was killed and replaced before he ever met her, and the young woman he knew for two years was really a spy named Rook. His superior decides to let the spy think their cover is intact and feed them misinformation.]]
* There is a reversal of this trope in Creator/IsaacAsimov's ''Evidence'', where it is implied that a man who was crippled in an accident created a replicant for himself, who replaced him by his own consent, [[spoiler: and eventually gets elected as the political leader of the entire Earth, ruling in a very beneficial manner.]]
* Creator/PhilipKDick's short story ''The Father-thing''. When an alien takes the place of the protagonist's father, he eats his insides, leaving only a dry, dead skin behind.

[[/folder]]

[[folder: Live-Action TV ]]

* The Slitheen from ''Series/DoctorWho'' kill ministers, skin them and wear the 'suits' using gas compression technology.
** Played much more tragically in Series 6, where [[spoiler:at the end of "The Almost People", a man who died and left a child behind is replaced by his duplicate, who has all the original's memories and feelings, but knows he's a duplicate.]]
* In ''[[Series/StarTrekDeepSpaceNine DS9]]'' episode "Homefront", Sisko convinces the president that security measures are needed to prevent just that. [[spoiler: It all was actually orchestrated by an evil admiral, though changelings do disguise themselves as people]]
* Happens from time to time in ''Series/KamenRiderKabuto'', as the [[MonsterOfTheWeek Worms]] can shape-shift into a perfect copy of any human. The most famous example is [[spoiler:Tsurugi Kamishiro, Kamen Rider Sasword]], who we later learn is a Worm who lost his memory as a Worm, BecomingTheMask in the process.
* ''Series/TheSarahConnorChronicles'':
** Cromartie pulls a similar schtick; growing a new synthetic skin, undergoing plastic surgery to resemble an out-of-work actor, then killing him and assuming his identity.
** Another terminator, [[spoiler: Vick Chamberlain, replaced a married man. Said man died in a car accident, and this terminator seems to explain his strange behavior by claiming brain damage.]]
** And [[spoiler: another terminator replaced Catherine Weaver, and is currently running her company with employees who knew her from before ''and'' has adopted Weaver's daughter!]]
** In "Allison From Palmdale" it is revealed that [[RobotGirl Cameron]] is a machine doppelganger of [[spoiler: Allison Young, a resistance fighter from the future who was "close" to John Connor. Cameron interrogates Allison and learns about her past, becoming an exact copy of her in mannerisms, and then kills her.]] Later on, after being captured by the human resistance, Cameron suffers damage to her processor that results in [[spoiler: [[BecomingTheMask her confusing herself with the "Allison" persona]].]]
** In the episode "Automatic for the People," [[spoiler: Carl Greenway is introduced. He is a power technician. Skynet makes a Terminator that looks exactly like him and sends it back in time to kill him, replace him, and blow up the nuclear power plant where he works.]] [[spoiler: Luckily, he and Sarah bond over the cancer that he survived. He has a scar on his arm from having his lymph node removed, which the Terminator does not have.]]

[[/folder]]

[[folder: Puppet Shows ]]

* ''Series/CaptainScarletAndTheMysterons''' eponymous Mysterons fit this trope to a T. ''"Possessing the ability to re-create an exact likeness of an object or person -- but first, they must destroy."''

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[[folder: Tabletop Games ]]

* The Tsochar in the ''Lords of Madness'' supplement for ''DungeonsAndDragons'' are tentacle monsters that can insert themselves into a humanoid host and either tag along harmlessly or violently usurp the original person.
** There are also doppelgangers, changelings, demonic and ghostly possession, several magic spells... Inventive players or [=DMs=] can find dozens of ways for a character or monster to replace someone or wear him like a puppet, with varying degrees of survivability for the victim.
* ''{{Exalted}}'' has this as an ability of the Lunars; they can become another creature if they ritualistically stalk it for hours, kill it, then drink its heart's blood. They can do the same thing for humans, but they can only pick up the specific form of the human they killed. However, there are Knacks that allow them to shift the appearance of a form they've acquired, and, if they're feeling humane, Knacks that allow them to assume a form temporarily after partaking of a non-lethal amount of blood from their target, or take a human form permanently after knocking them out, or even ''[[FetishFuel sleeping with them.]]''
* This is the central concept of [[http://storiesyouplay.com/44/ 44]], in which the [=PCs=] are people who've had a close relative or friend replaced by a robot, and the GM controls the Section 44 conspiracy. Brilliantly, player characters can be replaced during the game, and join the GM on the bad guy side.
* The roleplaying game ''[[TabletopGame/ChangelingTheLost Changeling: the Lost]]'' plays on this idea. The changelings of the title are actually the humans who were abducted (at any age, not just as babies) and taken away to Faerie; fetches, artificial beings crafted from random detritus and animated by TheFairFolk, take their place, and actually believe themselves to be the person they replaced. Getting your old life back may very well involve doing this, in reverse, to an innocent being who's totally unaware that it isn't really you.

[[/folder]]

[[folder: Video Games ]]

* The trope picture comes from the graphic-adventure game ''VisualNovel/{{Snatcher}}'', despite its oversimplification of the eponymous robots' preferred method of impersonating humans: grafting the replica skin and muscle tissue of their quarry over an exoskeleton in a [[PeopleJars People Jar]].
* The Soultaker from ''LimboOfTheLost'' stole [[spoiler:the Mayor of Darkmere]]'s skin to hide itself from the populace.

[[/folder]]

[[folder: Web Comics ]]

* In the webcomic ''[[http://www.ringtailcafe.com/starfireagency/ Starfire Agency]]'' Denver discovers that TheGreys that have been periodically abducting him replace some people with clones that have a hidden sleeper personality and keep the originals in tanks. He recognizes one of the people in tanks as [[spoiler: his girlfriend, who was replaced when she was ten,]] and another as [[spoiler: [[TomatoInTheMirror himself]]]].
* In ''[[http://www.willowsgrove.com/wordpress/ Willow's Grove]]'' people kidnapped by the Nexus are replaced by android replicas. In addition the Starblazer creates replicants of Fred and Becky to keep Max and Bob company while they're trapped on board.
* Played with in ''WebComic/CommanderKitty''. The Zenith project is replacing people tagged with iKnow devices with android clones in an attempt to "eliminate imperfection across the galaxy." ([[TeenGenius Fortiscue]] thought it [[http://www.commanderkitty.com/2012/01/01/seemed-like-a-good-idea-at-the-time/ seemed like a good idea at the time.]]) It only goes wrong(er) when his assistant Zenith [[ZerothLawRebellion gets a little too obsessed with her directive to eliminate imperfection]] and starts using them as her own personal army.

[[/folder]]

[[folder: Web Original ]]

* ''TheToymakersWorkshop,'' being based on the ''TabletopGame/ChangelingTheLost'' example, is about the construction of a fetch.

[[/folder]]

[[folder: Western Animation ]]

* This is the purpose of the eponymous conspiracy in ''WesternAnimation/TheZetaProject''. Its purpose is to allow the government to assassinate anyone it wants; they then send a holographic robot duplicate to prevent suspicion among the target's acquaintances.
* WesternAnimation/DarkwingDuck had an episode with alien cabbages. The cabbages would sprout a clone, then the cabbage would devour and capture the original.
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