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Killing for a Tissue Sample

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"Unfortunately, my patented cloning process has one nasty side effect: I have to cut you in half!"
Hamsterveil, Stitch! The Movie

If a character has special properties, other people usually want to know how to get or understand them, for reasons ranging from For Science! 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 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 Monster Organ Trafficking, Captured Super-Entity, They Would Cut You Up, and Borrowed Biometric Bypass. Compare Overdrawn at the Blood Bank. Contrasts with Kidnapped for Experimentation, where the entire person/creature is taken and kept alive so the scientist can experiment on it. Not to be confused with someone dying to get their hands on a box of tissues.


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    Anime and Manga 
  • Casshern of Casshern Sins 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.

    Film — Animated 
  • In Stitch! The Movie, Hamsterveil tries to make a clone army of Stitch, which would involve killing the original.

    Film — Live-Action 
  • Averted in Pirates of the Caribbean: The Curse of the Black Pearl 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 District 9 does some tests on Wikus to confirm his ability to use alien weaponry, then decides to kill him to examine his genetic material.
  • In Man of Steel, the Kryptonian survivors need an object called the Codex, which contains the DNA plans for reconstructing their species. One of 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 and invoked by Nyah in Mission: Impossible II, who injects herself with the last sample of a Synthetic Plague that the villains need for a Poison and Cure Gambit to stop them from killing her. All of the parties involved simply assume that it would be impossible to retrieve a sample of the virus from a freshly dead corpse.
  • X-Men: Days of Future Past: After studying Mystique's DNA, Bolivar Trask decides he wants more samples in order to create new kind of technology with Adaptive Abilities. Among the samples he needs are brain tissue, spinal fluid, and bone marrow, implying that, if he got the chance, he would pretty much pick Mystique apart piece by piece.

  • In Halo: First Strike, Sergeant Johnson turns out to be immune to the Flood. Halsey gives John the choice of giving the Office of the Naval Intelligence one of two data crystals. One directly mentions Johnson by name and outlines how 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 dissect Johnson in hopes of figuring out the cure. John struggles with which is better to give, and chooses the latter.
  • Animorphs #36 (The Mutation) features a race of inbred mutant Fish People 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 in the Vorkosigan Saga story "Labyrinth", in which Miles is sent on a mission to retrieve a sample stored in the muscle of a genetically engineered Super-Soldier. He's given a lethal injection for the super-soldier, but it's unrelated to fetching the sample. 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 Clan of the Cave Bear, 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 in The Reckoners Trilogy. 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 Hair-Trigger Temper, it's safer to kill them first.

    Live-Action TV 
  • Addressed in a Metal Hurlant Chronicles 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 Slashed Throat with a large pool of blood on the ground.
  • In the Star Trek: Deep Space Nine episode "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 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 M*A*S*H, 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 episode of Diagnosis: Murder, 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 Farscape episode "DNA Mad Scientist", the eponymous Mad Scientist wants a very large sample of Pilot's DNA, one of his arms (it regenerates). Of course, earlier, he claims that he needs to take genetic samples 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.
  • Sliders has Colonel Rickman, who kills for brain tissue to combat a brain fungus that he picked up in one of his alternate universe's wars.
  • In the Doctor Who episode "Deep Breath", both a chatty human passerby and a tyrannosaurus are killed by clockwork robots that have a use for some of their eye tissues. The man, at least, could surely have survived without his eyes.

    Video Games 
  • In Dragon Ball Online, it is Miira's goal to travel through time and do this to Goku, the strongest warrior in history, in order to make himself more powerful.
  • In The Last of Us, the Fireflies want to kill and dissect Ellie to see if her immunity to the cordyceps fungus can be adapted into a cure. Justified in that the fungus grows on the brain — it'd be virtually impossible to nonlethally get what they needed from Ellie.
  • Defied in Batman: Arkham City. 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.
  • Metroid Dread: The E.M.M.I.s that have been hunting down Samus throughout the game were reprogrammed by the Big Bad to obtain a sample of her DNA. As robotic probes designed for surveying alien wildlife, they already come with the necessary equipment. As Super-Powered Robot Meter Maids, said equipment is a three-foot metal spike that they will attempt to spear directly into her cranium if they catch her.


    Western Animation 
  • In a "Treehouse of Horror" episode of The Simpsons, it's discovered that Bart is 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.
  • Kipo and the Age of Wonderbeasts: In a flashback episode, Emilia 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, Emilia probably would've killed it even if it had been minding its own business.
  • Futurama:
    • In "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 "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 "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 "Cold Warriors", to stave off a cold epidemic (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.

    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.