->''"Unfortunately, my patented cloning process has one nasty side effect: I have to cut you in half!"''
-->-- '''Hamsterveil''', ''WesternAnimation/StitchTheMovie''

If a character has special properties, other people usually want to know how to get or understand them, for reasons ranging from ForScience to world domination. This means that they need to figure out how the special properties are created, and how they can be replicated. That means they need a sample of the blood or genetic material of the subject, which is reasonable enough. Then they kick it into Dramatic Storytelling and decide they don't just need a sample, they need the body. The dead body.

There are multiple reasons why this is a Bad Plan. Death is [[DeathIsCheap usually]] permanent, so if there were a screw up and they needed the subject alive, too bad; corpses aren't very talkative. It tends to give focus to the subject or their friends and make them fight you much harder than if you just wanted some blood samples. It's terrible PR, since the general public frowns on experimentation via murder. It's much better if the subject is alive so they can avoid all of those pitfalls and generate more genetic material or blood. However, captivity isn't as dramatic as impending death.

Related tropes include MonsterOrganTrafficking, CapturedSuperEntity, TheyWouldCutYouUp, and BorrowedBiometricBypass. Compare OverdrawnAtTheBloodBank. Contrasts with KidnappedForExperimentation, where the entire person/creature is taken and kept alive so the scientist can [[PlayingWithSyringes experiment on it]], and OrganTheft, where someone steals a vital organ from someone (i.e. a kidney) but leaves them alive (usually in a bathtub of ice). [[JustForFun/IThoughtItMeant Not to be confused with]] someone dying to get their hands on a box of tissues.

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!!Examples

[[foldercontrol]]

[[folder:Anime and Manga]]
* Casshern of ''Anime/CasshernSins'' is immune to the Ruin that affects every other robot; consequently, there is a rumor that eating him will grant eternal life. This is hinted at being true since Friender, a robot dog that took a chunk out of him, shows no sign of Ruin years later, but no one asks to slice off a chunk of his regenerating body, they just charge into battle and die.
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[[folder:Film -- Animated]]
* In ''WesternAnimation/StitchTheMovie'', Hamsterveil tries to make a clone army of Stitch, which would involve killing the original.
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[[folder:Film -- Live-Action]]
* {{Averted|Trope}} in ''Film/PiratesOfTheCaribbeanTheCurseOfTheBlackPearl'' initially, then played straight.
** The pirates avert the trope with Elizabeth. They let her believe she'll be sacrificed to free them, but all they need is a few drops of her blood on the gold, the implication being that they are doing it this way because they have ''plans'' for her once they are returned to a living state and can experience physical pleasures again...
--->'''Elizabeth:''' That's it?\\
'''Barbossa:''' Waste not.
** When it becomes William's turn, they are by this point rather frustrated and decide to spill it all just to make sure -- and provide greater dramatic emphasis for the effort to rescue him, of course.
* MNU in ''Film/District9'' does some tests on Wikus to confirm his ability to use alien weaponry, then decides to kill him to examine his genetic material.
* In ''Film/ManOfSteel'', the Kryptonian survivors need an object called the Codex, which contains the DNA plans for reconstructing their species. One of [[BigBad General Zod]]'s scientists discovers that the Codex has been fused with Superman. All it'd take to retrieve it is a cellular extraction, but Zod has vengeance on the mind and asks if Superman has to be alive for them to retrieve it. As it turns out, he doesn't.
* {{Inverted|Trope}} and {{invoked|Trope}} by Nyah in ''Film/MissionImpossibleII'', who injects herself with the last sample of a SyntheticPlague that the villains need for a PoisonAndCureGambit to [[CantKillYouStillNeedYou stop them from killing her]]. All of the parties involved [[FridgeLogic simply assume]] that it would be impossible to retrieve a sample of the virus from a freshly dead corpse.
* ''Film/XMenDaysOfFuturePast'': After studying [[VoluntaryShapeshifting Mystique]]'s DNA, Bolivar Trask decides he wants more samples in order to create new kind of technology with {{Adaptive Abilit|y}}ies. Among the samples he needs are brain tissue, spinal fluid, and bone marrow, implying that, if he got the chance, he would pretty much [[TheyWouldCutYouUp pick Mystique apart piece by piece]].
[[/folder]]

[[folder:Literature]]
* In ''Literature/HaloFirstStrike'', Sergeant Johnson turns out to be [[TheImmune immune]] to [[OurZombiesAreDifferent the Flood]]. Halsey gives John the choice of giving the Office of the Naval Intelligence one of two {{data crystal}}s. One directly mentions Johnson by name and outlines how [[DisabilitySuperpower his nerve condition makes him immune]], the other has the same information but omits his name and DNA. She warns John that giving ONI the former will likely cause them to [[TheyWouldCutYouUp dissect Johnson in hopes of figuring out the cure]]. John struggles with which is better to give, [[spoiler:and chooses the latter]].
* ''Literature/{{Animorphs}}'' #36 (''The Mutation'') features a race of inbred mutant FishPeople who want to kill the Animorphs with an elaborate machine to get their DNA to increase their gene pool. They aren't interested when it's pointed out that there's easier ways to get a DNA sample.
* {{Averted|Trope}} in the ''Literature/VorkosiganSaga'' story "Labyrinth", in which Miles is sent on a mission to retrieve a sample stored in the muscle of a genetically engineered SuperSoldier. He's given a lethal injection for the super-soldier, but it's unrelated to fetching the sample. [[spoiler:Rather, the scientist believes that Miles won't help rescue the said super-soldier and that death is more merciful than what she faces.]]
* In ''Literature/ClanOfTheCaveBear'', the medicine woman Iza teaches Ayla about the healing properties of various plants. However, Ayla pulls the whole plant, killing it, so Iza has to teach her not to take the whole plant so that it will continue to grow and provide medicine for the future.
* {{Justified|Trope}} in ''Literature/TheReckonersTrilogy''. It turns out that the machines that replicate an Epic's power only needs a cell culture, but the way that Epics are connected to their powers lets them (painfully) sense when and where those machines are used. Since Epics are almost always supervillains with a HairTriggerTemper, it's safer to kill them first.
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[[folder:Live-Action TV]]
* Addressed in a ''Series/MetalHurlantChronicles'' episode in which the subject willingly gives his blood and life to save his dying princess, specifying that all the blood is needed. However, it's still played straight since no effort is made to capture the blood, and we last see her lapping at his SlashedThroat with a large pool of blood on the ground.
* In the ''Series/StarTrekDeepSpaceNine'' episode "[[Recap/StarTrekDeepSpaceNineS06E12WhoMournsForMorn Who Mourns for Morn?]]", a group of thieves show up on the station to get at Morn's horde of gold-pressed latinum from a heist they had all participated in years earlier, and which Morn has willed to Quark. The delivery is coded to Quark's thumbprint, and one of the thieves threatens to kill Quark and [[BorrowedBiometricBypass take his thumb]] if he doesn't cooperate. One of the other thieves points out that it'd be more than a little suspicious if they showed up with a bloody severed thumb to get at the delivery.
* In an episode of ''Series/{{MASH}}'', Margaret thinks that she might be pregnant. She asks Hawkeye to do a rabbit test on her (where they inject a rabbit with a urine sample from a possible mother and then dissect the rabbit to examine its ovaries). The only female rabbit available is Radar's, who refuses to allow them to kill his pet, but he will let them do the test if they promise that the rabbit won't be killed -- so the doctors do an ovariectomy on Radar's rabbit.
* In one [[Recap/DiagnosisMurderS2E16PlayingForKeeps episode]] of ''Series/DiagnosisMurder'', the killer turns out to be a doctor who specializes in studying genetics, and his intended victim has a unique trait in her genes that he's convinced will further his research.
* Not quite killing but still excessive; in the ''Series/{{Farscape}}'' episode "[[Recap/FarscapeS01E09DNAMadScientist DNA Mad Scientist]]", the eponymous MadScientist wants a very large sample of Pilot's DNA, one of his arms ([[GoodThingYouCanHeal it regenerates]]). Of course, earlier, he claims that he needs to take genetic samples [[EyeScream from the crew's eyes]] in order to determine the locations of their homeworlds, and when Crichton asks why he can't just use some skin, he states that would be the case if he were working at the level of mere DNA.
* ''Series/{{Sliders}}'' has Colonel Rickman, who kills for [[BrainFood brain tissue]] to combat a brain fungus that he picked up in one of his alternate universe's wars.
* In the ''Series/DoctorWho'' episode "[[Recap/DoctorWhoS34E1DeepBreath Deep Breath]]", both a chatty human passerby and a tyrannosaurus are killed by clockwork robots that [[HumanResources have a use for]] [[EyeScream some of their eye tissues]]. The man, at least, could surely have survived without his eyes.
[[/folder]]

[[folder:Video Games]]
* In ''VideoGame/DragonBallOnline'', it is [[BigBad Miira]]'s goal to travel through time and do this to Goku, the strongest warrior in history, [[LegoGenetics in order to make himself more powerful]].
* In ''VideoGame/TheLastOfUs'', the Fireflies want to [[TheyWouldCutYouUp kill and dissect Ellie]] to see if her [[TheImmune immunity]] to [[FesteringFungus the cordyceps fungus]] can be adapted into a cure. {{Justified|Trope}} in that the fungus grows on the brain -- it'd be virtually impossible to nonlethally get what they needed from Ellie.
* {{Defied|Trope}} in ''VideoGame/BatmanArkhamCity''. Ra's al Ghul knows that Batman needs his blood in order to generate the cure for the Joker's illness. He attempts to force Batman's hand on the issue, but Bats simply whips out a sample-collector and nonlethally gets what he wants.
* ''VideoGame/MetroidDread'': The E.M.M.I.s that have been hunting down Samus throughout the game were reprogrammed by the BigBad to obtain a sample of her DNA. As robotic probes designed for surveying alien wildlife, they already come with the necessary equipment. As SuperPoweredRobotMeterMaids, said equipment is a three-foot metal spike that they will attempt to spear directly into her cranium if they catch her.
[[/folder]]

[[folder:Webcomics]]
* ''Webcomic/AccidentalCentaurs'' [[OrphanedSeries went on hiatus]] with a {{Cliffhanger}} about whether Lenny is going to kill Stavvros to get a DNA sample.
[[/folder]]

[[folder:Western Animation]]
* In a "WesternAnimation/TreehouseOfHorror" episode of ''WesternAnimation/TheSimpsons'', it's discovered that Bart is [[TheImmune immune]] to the zombie plague, so a bunch of other (non-zombie) people plan to eat him in order to become immune. Eventually, he just swims in the soup that they all eat.
* ''WesternAnimation/KipoAndTheAgeOfWonderbeasts'': In a flashback episode, Emilia [[spoiler: and her brother]] go to the surface to collect cell samples from Mutes. While searching, she sees a mutant spider, kills it with her crossbow, and then extracts a hair from it. Justified here in that the spider was ''attacking'' her; she killed it in self-defense. Then again, [[BigBad Emilia]] probably would've killed it even if it had been minding its own business.
* ''WesternAnimation/{{Futurama}}'':
** In "[[Recap/FuturamaS2E10ACloneOfMyOwn A Clone of My Own]]", to sneak into the Near-Death Star to rescue the Professor, the crew need a DNA sample from him. Fortunately, they can get one from the Professor's clone, Cubert. Rather than one cell, however, Bender takes out a liter's worth of Cubert's blood, telling the guard to "keep the change".
** In "[[Recap/FuturamaS4E12TheSting The Sting]]", Professor Farnsworth prepares to test Leela's brain to see if she's sane... by putting her in a guillotine.
--->'''Leela:''' Professor! Can't you examine my brain without removing it?\\
'''Farnsworth:''' Yes, easily.
** In "[[Recap/FuturamaS6E1Rebirth Rebirth]]", the Professor uses stem cells to revive the crew. When Fry points out how controversial stem cells were in his time, Farnsworth explains that he's using adult stem cells... harvested from adults whom he had killed for their stem cells.
** In "[[Recap/FuturamaS6E24ColdWarriors Cold Warriors]]", to stave off a cold epidemic ([[WeWillHavePerfectHealthInTheFuture the common cold was eradicated centuries ago]] and people no longer had immunity), the Professor needs to get a sample from Fry... by grinding him up into a slurry. Fortunately, Fry remembers that he had a cold sample sent to space when he was a kid, and they decide to spare Fry and get that sample instead, much to the Professor's disappointment.
[[/folder]]

[[folder:Real Life]]
* Rabies testing usually requires brain tissue, so wild animals (and some domestic animals) suspected of having it are killed before the lab can know for sure.
[[/folder]]
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