Borrowed Biometric Bypass

"Thanks for lending me a hand there, mate."

Kryten: Logically, sir, there is only one way you could possibly have opened that door. I feel quite nauseous. — Where is it?
Lister: Where's what?
Kryten: [horrified] Oh, sir, you've got it in your jacket!
Lister: I got us out of the hold, didn't I?
Kryten: Sir, you are sick! You are a sick, sick person! How can you possibly even conceive of such an idea?
Lister: Hey, shut up... or I'll beat you to death with the wet end.
Kryten: Sir, if mechanoids could barf, I'd be onto my fifth bag by now...

— Red Dwarf, "The Inquisitor"

Once upon a time, infiltrating a base was pretty easy: just knock the guards out, take the keys, and get in. Fortunately, modern high-tech facilities, or in The Future have more cunning devices, and can identify the guards by unique biological features, such as handprints or retinal scans. These cunning devices are reliable, efficient, and not prone to believing just anyone who happens to be wearing the right uniform. Great, huh?

Unfortunately, the more dangerous individual won't need to get your guards to agree: He'll find someone with the right access and engage in some very unpleasant surgery. He may remove a guard's eye or finger, or he may simply lop off his or her head and hand with a big ol' blade. Then, equipped with those body parts, he'll simply apply these to the biometric authentication device in question and get through.

This raises the question of whether or not any such devices would be able to tell whether the hand or eye in question was attached to a living body. In reality, this actually is a key consideration in designing biometric security. Some devices (the cheaper ones, mostly) are vulnerable to this kind of thing. Needless to say, such a weakness is considered an absolute disqualification for usage in any classified government facility.

The violent means is rarely used by good guys unless they're Late to the Tragedy and there's already a surplus of corpses, as it's definitely on the morally dubious side of things, even if you don't kill the victim. A more moral person may have to talk or threaten the guard into showing his "Eye-D", or simply wrestle the poor mook into place. However, one way to bypass the identification system without violence is to simply lift fingerprints left on an object or acquire shed materials such as the target's hair. Another option is to wiretap the biometric sensor so that the signal from an authorized subject can be recorded and used later in a replay attack. Such tactics are among a Master of Unlocking's arsenal for getting past locked doors.

Note that this is not about bypassing biometric scanners in general. This is about using the body parts of those who have access to bypass the scanners.

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Examples:

Advertising

• An online ad for HP Laptops uses a cute version of the "harmless" variety. A woman is (pretending to be) asleep on her couch. Her young son takes her hand, presses the thumb to the laptop's fingerprint reader, and starts watching cartoons.

Anime & Manga

• In one case from Case Closed, Dr. Agasa is kidnapped by an Outlaw Couple who've mistaken him for the president of Suzuki Security because they need the president's eye to open a safe they've stolen. The issue of whether a corpse's eye can be used is adressed: the iris lock is supposed to only work on living eyes, but after Agasa takes a bullet to the thigh, the criminals remark that even if he dies, the eye won't be rendered unusable for five hours.
• Junko Enoshima does this in Danganronpa 3: The End of Hope's Peak High School by spooning out the eye of one of the members of the school board in order to access the room where Izuru Kamukura is held. For extra disturbing points, she used the spoon to eat some microwaved curry rice just beforehand, purely to make the guard suffer more.
• Future Diary: Averted, when Eleventh has hidden himself within the safe of the Gasai family which can only be accessed by members of said family. Given that he's under the assumption that the Yuno Gasai we have followed throughout the series is an impostor, he is completely taken off-guard when she gets into the safe very easily. That's because she's not an impostor, but a Yuno Gasai from a different timeline who killed this timeline's Yuno to replace her. Naturally, the Yuno we have followed all the time has the real eyes necessary to open the safe all the time and doesn't need to steal someone else's eyes.
• Inuyasha: In a fantasy example, Sesshomaru grafts a human arm onto his body to get around Tessaiga's "cannot be wielded by a full demon" limitation.
• In JoJo's Bizarre Adventure: Stone Ocean, Anasui uses an unconscious guard's eyes to open the security gate into the maximum security ward to reach Jolyne.
• In Psycho-Pass, Makashima uses extracted eyeballs and severed fingers to enter a facility that uses biometric security rather than the setting's more prevalent cymatic scan security.
• An unusual example occurs in Tokyo Ghoul, providing one of the clues to the true nature of the Government Conspiracy. Early on in the series, Half-Human Hybrid Kaneki is able to bypass the scanner gates used to detect ghouls. The reason for this is only revealed in the sequel: It's because the scanners have been programmed to ignore certain ghouls, including the one Kaneki received an involuntary organ transplant from.
• Vandread: In Episode 1 of Stage 1, Hibiki uses a false palmprint copied off a person with the right clearance to sneak into the Ikazuchi's Vanguard bay in order to take his 'partner'. It almost failed because he forgot to moisten the copied prints, which he manages to do at the last second with some spit. Which probably only worked because Hibiki had been recorded as a passenger when he was an infant.

Audio Plays

• In the Big Finish Doctor Who audio play The Apocalypse Element, the Daleks make their way through the capitol using the eyes of dead guards to bypass the retinal security locks.

Comic Books

• In Batman stories:
  • The Joker once gained access to a government vault by Joker toxin-ing the guards and dragging one over to a biometric scanner. The vault, incidentally, held Doomsday.
  • Arkham Asylum: Living Hell:
    • Used by fellow Arkham inmate Jane Doe in an attempt to escape through an emergency exit requiring a fingerprint scan, retinal scan, and voice ID. As Jane's modus operandi is wearing the skin of the people she kills and taking over their identities, she was well prepared, bringing her latest victim's severed hand and preserved eye, plus a recording of the victim pleading for her life.
    • Killer Croc bit off a guard's hand, but didn't eat it; somehow or other the lunatic scavenger Junkyard Dog got a hold of it, preserving it in a jar and, when he gets the chance, using it to bypass a handprint scanner to aid in his escape.
  • Night of the Owls: In one of the issues, Mr. Freeze kills a guard by flash-freezing him, then snaps off one of the corpse's fingers and uses it to bypass a locked security gate.
• In Cavewoman: Markham's Mansion, Meriem severs Hugo Markham's hand to force him to drop his sword. She later presses the severed hand against the palm reader to activate all the booby traps.
• Parodied in Doomsday Clock. When the obnoxious bank manager is being a dick to her, Marionette responds by slicing off part of his finger. Only afterwards does she realize that the vault has a hand scanner, and for it to scan properly, they need the part of his finger she just removed.
  Marionette: Shit. Did anyone see where his finger went?
• In Ghostbusters (IDW Comics), Gozer wants his lost power back, and possesses Ray, trying to use him to open the containment unit. This also happened with Peter back in The Real Ghostbusters, although this time, the Ghostbusters have security measures in place to prevent this.
• Hack/Slash: In Slice Hard, Ashley cuts the fingers off a guard and uses them to bypass the fingerprint scan on the biometric lock on the lab.
• Subverted in Harlem Heroes. Patrice copies a guard's fingerprints onto a latex glove and his retina onto a blank contact lens to compliment the guard's keycard. Unfortunately, that's not enough for the door in question, which also requires a chromosomal sample to open. Deacon simply blows the door open instead.
• Judge Dredd spinoff Tempest had the protagonist arrested at one point. He breaks free and steals a pair of lawgivers. To bypass the ID lock and Self-Destruct Mechanism, he tears the skin from the hands of the judges he disarms.
  • The main strip itself had an episode where a judge lost their hand along with the lawgiver it was holding. Two random citizens find it and discuss selling it. One says it's a bad idea, while the other notes that with the corresponding judge's hand still attached, that the Self-Destruct Mechanism is not a problem.
• In the final issue of Paranoia, King uses a robot face and hand to get access to Friend Computer.
• In Shaman's Tears, a guard mocks Animus while sticking his hand in his cage. Animus tears off the man's hand which he then uses to open the lock on his cage and escape.
• In one S.H.I.E.L.D. comic, Phil Coulson is trying to get into an Auction of Evil by posing as Batroc. At the same time, the field team is fighting the real Batroc. When Coulson is told he needs a retina scan, the field team manage to scan Batroc's eyes, enabling Fitz to upload his retina prints to Coulson's contact lenses just as they're being scanned. They were hoping for a DNA scan, so all they'd need was a hair sample.
• In a Weird Worlds story, when an elevator Lobo's hijacked reaches his destination, the doors won't open. The elevator attendant explains that they're tied to his DNA, the sensor for which is several floors up, where they just came from, but the elevator won't go back up because he didn't have the chance to use the sensor when Lobo got on. Since there's no ceiling between them and the sensor, Lobo just blows the attendant's brains out, splattering his blood on the sensor.

Fan Works

• Danganronpa: Komm Susser Tod: In Chapter 5, Ukyo's severed left arm is used to frame him for murder — Monokuma's office, where the murder occurred, has a check-out display registering fingerprints announcing who has just left, and the actual culprit used it to make it seem as though he was there.
• Eleutherophobia: How I Live Now has a variation where the bypasser is borrowing his own biometrics. Tom needs to hijack the Blade ship (of his own volition this time), and is the only one who can unlock it because the Yeerk who once controlled him used his biometrics as a security override.
• In Hunter (UnwelcomeStorm), Armsmaster has his armor set to lock down if his arm is severed from his body so no one can use his fingerprints for a biometric scan.
• In Kara of Rokyn, the titular character needs to stay in the Fortress of Solitude while she's trained by Lady Shiva. Superman isn't comfortable with the idea of leaving his depowered cousin alone with an infamous martial arts master and assassin, so he warns he's programmed the door to open to Kara's touch, and a heat-sensor will prevent any "dead hand" business. Shiva cheekily retorts there're ways around it.
  Looking at Kara, Kal said, "The door will open to your or my touch now, but to no one else's. It also has a heat-sensor, which will prevent anyone holding a dead hand to it."
  Shiva knew that bit was meant for her. "I am flattered by your trust, friend Superman. A dead hand could be warmed in a kitchen, if one was desperate to get out."
• Mass Effect 2 AU Lanius: During the Shadow Broker DLC, the Butcher takes off one of Liara's hands in order to use it to access the Broker's base.
• In Firefly fanfiction Where the River Flows, River and Mal force a mook to use his retinal scan to gain entry to a place where Jayne is being held.

Films — Animation

• In Appleseed Alpha, the bioroid Iris is revealed to have a Meaningful Name when her eye activates the Land Battleship, so the Big Bad forces her to look into the retinal scanner. It's implied she was custom-made for this sole task.
• In Batman vs. The Teenage Mutant Ninja Turtles, Ra's al Ghul accesses Joker's cell by amputating a guard's hand to get past the scanner.
• In The LEGO Batman Movie, the Riddler steals an arm from Jeff, a Gotham Energy Facility worker, and uses his handprint to give the rest of the Rogues Gallery access to the reactor core.

Films — Live-Action

• The 6th Day. Adam shoots a female goon in the hand, blowing off her thumb which he then uses to start up a truck, and get into high-security areas in the cloning facility. However, the woman who lost her thumb has been cloned again, so when she tries to get into the same area the system refuses her, tipping off the bad guys what is happening.
• The ship in Alien: Resurrection had locks that could only be opened by a cleared individual breathing onto a scanner. Call has a keyring full of sprays, presumably containing substitute versions of the officer's spit.
• Angels & Demons: A woman uses the eye scanner at CERN, not realizing until she touches her chin that there's blood on the chin rest below it. She's then horrified to discover an eyeball lying on the floor, and then a colleague with his eye cut out.
• In Back to the Future Part II, a brief glimpse of a news article in 2015 says "Thumb Bandits Strike Again". Since all monetary transactions in that future are done by thumb scanners, criminals would start to steal victims' thumbs.
• The Batman (2022): Used for a sick joke by the Riddler when he cuts off the thumb of his first victim, the Gotham City mayor (apparently before he'd actually died), and leaves it attached to the Mayor's USB drive — a literal thumb drive. They then have to use the thumbprint to unlock the drive, much to Gordon's disgust.
  Gordon: Oh, this guy's hilarious...
• In Batman v Superman: Dawn of Justice, Lex Luthor carves off the fingerprints of General Zod's corpse with a kryptonite scalpel and uses them to gain access to the crashed Kryptonian scout ship. Using this access as a stepping stone, he creates access for himself.
• The Big Sick: A mild example: Kumail gets into a comatose Emily's phone at one point by pressing her thumb on the screen.
• Blade Runner 2049 has a version of this without the dismemberment part — in order to break into an important LAPD computer, Luv picks up the corpse of Lieutenant Joshi and scans her eye for it. Then she just casually lets the body thud to the floor as she conducts her business.
• Charlie's Angels (2000) has them steal the fingerprints (off a beer bottle) and a retina scan (with a tuba) of two VPs, both of which have to be used simultaneously to open the vault. They then create a glove and a contact lens with the print and the scan.
• Proving you don't have to live in a high-tech world to use this trope, in Conan the Barbarian (2011), Conan cuts off a jail guard's head and holds it up to a torture chamber's small window, allowing the torturer to recognize it's his "fellow guard" knocking. As soon as the man opens the door, Conan knocks him silly with the head.
• In The Film of the Book of The Dead Zone, John Smith has a vision of Gregory Stillson as president. Stillson is hot to launch a nuclear strike at the Soviet Union, but to activate the Nuclear Football, he needs a general's handprint scan in addition to his own. Stillson tells the general, "Put your hand on that pad, or I'll cut it off and do it myself!"
• Simon Phoenix in Demolition Man gets through a door locked with a retina scanner by removing the authorized man's eye. Surprisingly having a pen jammed into it (to hold it with) doesn't seem to obscure the retina at all. Upon learning that all transactions are performed through microchips implanted in the user's hand, John Spartan notes that Phoenix can't mug anyone for money, "...unless he rips off somebody's hand, and let's hope he doesn't figure that one out." This one goes untested, and presumably they could always cancel the account of anyone minus a hand.
• Subverted in District 9. Since the alien weaponry can only be used by an alien hand, various attempts are made to use severed arms to fire the guns. That doesn't work, though, since the arms need to be alive.
• In Doom the movie, Sarge takes the severed arm of a dead scientist and places the palm on an access scanner to obtain the BFG.
• In Doomsday, a dying infected man armed with an axe uses this method to break into the building sheltering the UK's Prime Minister.
• In Double Team, Jean-Claude Van Damme's character cuts out the skin of his own thumb to provide time-needed biometrics while he is elsewhere.
• Used as a threat in Dragon Fighter. Stuck in an underground research facility with a raging dragon, the main character asks a lab technician for his laptop, which is needed to let everyone out. The technician tells him that the laptop is in his room, which is locked with a biometric lock. But since the monster is between them and the room, he is unwilling to go there. Frustrated, the main character grabs a cleaver and nearly hacks the guy's hand off in order to scare him to come with him.
• Entrapment: To access International Clearance Bank, the chairman's retinal scan is needed. A set of goggles is made up to fake this scan.
• A robotic version appeared in Futureworld, the sequel to Westworld. A door has a device that scans the retinas of anyone trying to get in. To pass, you must have a pattern that only robots possess. The heroes deactivate a robot and rip off its face, then use the face (and its eyes) to fool the device.
• A healthy trade for blood samples, urine samples, fingerprints, dandruff, and hair existed in the movie Gattaca. The protagonist used this to fake the identity of another man whom he paid for the samples, but presumably others used the black market in biologicals for more nefarious purposes.
• A non-lethal version in Ghost in the Shell (2017). Major simply hauls over a Yakuza goon she's knocked unconscious and uses his thumbprint to open the futuristic handcuffs he placed on her wrist earlier.
• Downplayed in I Am Mother. The droid Mother has to have a damaged hand replaced, and Daughter later uses it to bypass various security locks in the compound.
• James Bond:
  • In Die Another Day, Bond and Jinx get past a hand scanner by severing the arm of a recently killed henchman and pressing it against the scanner.
  • In Never Say Never Again, the remake of Thunderball (both starring Sean Connery as Bond), a bad guy had an eye transplant to get past a retinal scanner protecting some nuclear weapons.
  • A harmless version in Tomorrow Never Dies, where he uses a cell phone gadget that scans the print of whoever used the device last and then shows the phone display to the thumbprint scanner.
  • Played with in Diamonds Are Forever: To assure that she's really talking to her contact, Tiffany secretly tests the fingerprint of the drink tumbler he was using. Since the "contact" is really James Bond, we expect he'll be caught, but the fingerprint is a match. We later find he's wearing a thumbprint skin of the guy he's impersonating. Good thing she tested the correct finger.
• In The Man from Toronto, Randy and Teddy discover that the superweapon that Marin, Randy's latest client, intends to assassinate the president of Venezuela with requires Mr. Green's thumbprint in order to activate it. Randy then escorts Teddy out of the room while the sounds of Mr. Green screaming in agony and a finger being severed are heard offscreen, after which Randy walks out with a thumb in Teddy's Cheetos bag. It later turns out that Randy actually cut off a thumb from one of Marin's slain henchmen, having never intended to help Marin's coup attempt.
• Marvel Cinematic Universe:
  • In The Avengers (2012), Loki and his minions use a fancy piece of stolen S.H.I.E.L.D. tech that lets them scan someone's eye and turn it into a hologram good enough to fool a retina scanner. Loki probably didn't have to jam it right into the poor man's eye socket, though...
  • In Captain Marvel (2019), Nick Fury fools a thumbprint scanner by lifting an Air Force officer's print using a piece of scotch tape.
  • Shang-Chi and the Legend of the Ten Rings: While in a high-speed chase out of the Ten Rings compound, Shang-Chi's group approach a heavy gate that requires a hand scan on the dashboard to open. They grab a downed Ten Rings mook and press his hand on the scanner in time, opening the gate, and then press the "close" button so the car tailing them crashes into it.
• In Minority Report, the protagonist's wife used his eye to enter the prison where he's being kept. The eyes are actually his own leftover eyes after he gets a new pair of eyes to hide his identity. This invokes a Fridge Logic issue as to why his eyes have not been revoked access after he is captured and put in prison.
• Attempted in The Mummy (2017) to escape Dr. Jekyll's office. Turns out Mr. Hyde has different fingerprints...
• In National Treasure, Gates lifts Chase's thumbprint off a wine glass and applies it to a thumb cover on his own hand to infiltrate the vault storing the Declaration of Independence.
• In Pacific Rim, the portal is keyed to open only to Kaiju, so in order to get past that restriction, Gipsy Danger tackles the final one and dives through the portal with it, killing it on the way down.
• In Red Notice, Voce's vault has two explicit (faceprint and voiceprint) and one implicit (passcode determined by random number generator program running on a thumbprint-locked smartphone) biometric lock. The protagonists lift a print from a glass to unlock the phone and use face/voice-altering software to spoof the other two.
• In Resident Evil: The Final Chapter, Alice tries to ride an Umbrella Corp. motorcycle, but it detects she isn't an Umbrella employee and electrocutes her. The second time she finds one, she chops off Isaacs' hand and presses it to the handlebar, which works. She drops the hand and it is quickly eaten by a zombie, but she is still able to ride it.
• In Rogue One, Cassian uses the hand of an unconscious Imperial officer to open the vault room. Apparently he tries to use the wrong hand, forcing Kaytoo to prompt him with "Right hand!"
• Used in Shoot 'Em Up. Hertz smugly informs Smith that the gun he just took from his mook has a safety that requires a thumbprint to activate. Cue Smith removing the mook's hand from his pocket. Hertz grabs a knife and charges Smith as he presses the dead thumb against the grip sensor. It doesn't look like it's going to work for a moment, then the gun fires.
  Smith: Nothing like a good handjob.
• In The Snowman (2017), the villain kills a police detective and chops off her index finger in order to gain access to the fingerprint-protected police database.
• In Spaceballs, Lone Starr knocks out a guard and uses his hand to get into the self-destruct device chamber.
• The Suicide Squad. When breaking into Jotunheim, Peacekeeper opens the door by repeatedly smashing The Thinker's face into the retinal scanner until it works, hard enough that it cracks the plastic housing in the process.
  Thinker: Son of a bi—!! [device beeps affirmatively]
• Subverted in TAU where a very freshly severed hand works to bypass a biometric-locked door the first time, has to be rubbed vigorously the second time due to the hand rapidly cooling, and by the third door completely fails to work.
• Ultraviolet (2006) has a system to scan someone entering a secure facility to make sure they aren't vampires. It involves two thick needles stabbing the subject in the wrists. Getting around it by temporarily altering one's blood seems fairly simple.
• Zombieland: Double Tap shows how smart the "Hawking" zombies are by having one using the eye of a nearby corpse (held in the mouth, no less!) to go through a retinal scanner that was keeping a prospect victim behind a safe door.
• In Zygote, the creature assimilates the bodies of those it has killed, allowing it to get past the facility's fingerprint scanners. Before performing a Heroic Sacrifice, Quinn cuts off his own finger so Barklay will gain access to a corporate safe room, but the computer doesn't accept it. At the end, Barklay chops off one of the creature's appendages for the same reason, although she has trouble locating a finger with the proper security credentials.

Literature

• In the Dan Brown novel Angels & Demons, physicist Leonardo Vetra gets his eye cut out to get past a retinal scan.
• Area 51: Garlin severs Lisa's hand, which opens up a secret place at Stonehenge with the palm print.
• Artemis Fowl:
  • In The Eternity Code the protagonists are able to spoof the Big Bad's voice print, retinal scanner, and weight scale with fairy technology; but the fingerprint reader is some sort of gel-based technology that takes a three-dimensional reading of the digit so they need to cut it off while he's sleeping (they reattach it with magic when they're done). The Big Bad turns out to be waiting inside the room (he had a body double's prints set to work for that one night), and admits he can't figure out Artemis got around that lock without even waking the person up.
  • In a later book, the fairies have one that is specifically designed to detect a pulse in order to prevent this (justified due to the fact that it was designed by Foaly).
  • The final book has the ultimate form of this: the use of Opal's clone to deactivate her Doomsday Device.
• Daemon: In Freedom, this is a favourite tactic of the Major, who rescues girls from brothels, gets them darknet accounts and then beheads them to steal the identities, keeping them chemically alive to spoof the biometrics. He tries to pull this off on Loki, taking the man's eyes, fingertips, and tongue, but is caught before he can actually assume the identity.
• In Danny Dunn, Scientific Detective, when Danny learns that the kidnapped man's handprint is necessary to open a vault, he asks if the scanner will still read the print if the hand is cold. It takes a few moments for the other characters to realise what he is hinting at.
• In Kim Newman's Dark Future novel Krokodil Tears, via a severed hand, this is how Jessamyn bypasses the security system locking down Bronson Manolo's DeLorean in Dead Rat.
• The Frugal Wizard's Handbook for Surviving Medieval England: The Dimensional Travelers' Smart Guns are biometrically locked. Ealstan hears that the strange weapons will only work for their wielders and, at the end, shoots the Big Bad dead with a gun that still has its owner's severed hand clutching the trigger.
• In Halo: First Strike, UNSC headquarters has finger scanners... which release a blood-drawing needle during the scanning.
• In the Known Space universe, organleggers were known to harvest people for their organs. In one "Gil the ARM" story, it's noted that eyes are particularly in demand by criminals, to get past retina scanners with transplanted eyes from some organlegger victim.
• In the first The Last Chancers book, the team has to bypass a palm scanner that can detect whether the hand still has a pulse running through it. They circumvent it by removing the hand of an authorized officer, then surgically attaching it to one of the team member's wrists, via some tubes so he can hide it in his pocket.
• The League of Peoples 'Verse: Discussed in Ascending. Uclod demonstrates his Living Ship's security features to Oar, including the fact that it won't operate until confirming his DNA, palmprint, and fingerprints. Oar is unimpressed:
  Oar: That is foolish. If criminals wished to impersonate you, they could simply cut off your hand. Then they could rub the detached member against the wall—
  Uclod: Whoa! Just whoa. What is wrong with you, missy? How can such grisly ideas pop into such a pretty head?
  Oar: I am simply practical. Unlike your Zarett's security precautions, which would seem to encourage villains to amputate—
  Uclod: Hush! Right now. Not a word.
• In Sergey Lukyanenko's A Lord from Planet Earth amongst one of the Precursors' artefacts there are little one-time use devices capable of making planets barren wastelands. However, they need to be activated by a human hand. Attached to a living human being capable of reasoning its activation. Yes, they tried other options, including a severed warm human hand.
• Something similar in Lois McMaster Bujold's Mirror Dance, although here it's a code-key embedded in a ring, not a biometric. Sounds squick-free? No, because the ring in question is apparently riveted to the owner's finger bone and quite impossible to remove... And to get past the lock requires both the ring and a palm print. The palm locks in that verse actually do read heat, pulse, and electrical conductivity — as the protagonist points out, "dead hands don't open palm locks." Mark had to use some super-assassin hacking skills to get past that.
• In the opening scene of John Varley's The Ophiuchi Hotline, the mysterious agents helping the heroine escape from death row start by amputating her arm so they can replace it with one from someone who has access to the DNA-coded prison locks. She isn't worried, though, because cloned parts and limb transplants are routine, simple procedures in this universe. (Which leads one to wonder why DNA-sensitive locks would be considered reliable security measures in the first place.)
• In Isaac Asimov's Robots and Empire, two villains disagree on how best to perform their mission. One has a gun. The other's thumb is needed to work the required equipment. The armed one states that if blows the other's head off, the thumb will be quite intact.
• Star Wars Legends:
  • Rebel Force: Trapped has Luke Skywalker going through an Imperial base with a stolen passcard just fine until he reaches a palm scanner. Fortunately, it was guarded by the only two stormtroopers he'd encountered in the base who were inclined to shoot first, so he could kill them and use one's hand without violating his Martial Pacifist preferences.
  • Similarly, The Han Solo Trilogy has Han infiltrating an Imperial Dreadnaught to bribe an Admiral as part of a plan to fend off an expected Imperial attack on Nar Shaddaa, only for Darth Vader to show up and execute the Admiral via Force Choke. Han manages to avoid being detected by Vader, and briefly contemplates stealing the bribe money, but notes that he'd have to trying gouging the dead man's eye out to bypass the retinal scanner protecting the safe in his office, which is too repulsive.
  • Legacy of the Force: In the novel "Invincible" Jaina Solo infiltrates the star destroyer Anakin Solo — the flagship of her brother Darth Caedus (fka Jacen Solo). In addition to wearing a GAG Captain's uniform, she also forces a crew member to help her past biometric checkpoints so she can access the prison section of the Solo.
• In the Warhammer 40,000 Ciaphas Cain novel Cain's Last Stand, the titular hero expects Varan's forces to try this, so as he and his cadets are escaping the governor's palace he puts a lasbolt through the genecode scanner that controls the entrance to the escape tunnel.
• In one of the Women of the Otherworld books, the doors of the top-secret facilities are unlocked by fingerprint readers embedded in the door knobs. Our hero ambushes a guard and applies the logical solution to their problem.

Live-Action TV

• Done in 7 Days (1998) when Frank beats up a guard and then realizes he needs a valid handprint to pass a secure door.
• Alias: During Marshall's All Up to You story, he accidentally shoots a foe while attempting to furtively assemble a Scaramanga Special. With the enemy dead and unable to be bluffed into allowing him past, he has no choice but to remove his eyes, coached by Jack. The first attempt, with a knife, doesn't go so well, but then he finds a spork, which works better.
• In Angel, Angel has to get into Wolfram & Hart, so he kidnaps Amoral Attorney Lilah Morgan and says he wants the same thing from her that he got from Lindsey (a colleague who had a hand amputated by Angel). Cut to Lilah sensibly pressing her still-intact thumb against the scanner as Angel waits menacingly by her shoulder.
• Altered Carbon has a scifi variation, as it takes place in a future where people can transmit their digital personalities to other cities or planets, which are then downloaded into cloned bodies. There's a murder weapon that was kept in a safe which only the victim and his wife had biometric access to, but it's pointed out that the killer could have used one of their cloned bodies.
• In Avenue 5, the ship's First Engineer, Joe, is the only person with authentication to dock. Unfortunately, he is also dead, meaning the other engineers have to grab a plastic bag and retrieve his hands and head from space. Even more unfortunately, space is a vacuum, so by the time they reach Joe's body, all the useful parts have imploded.
• In Babylon 5, the links all the crew have on their hands are coded so that only authorized personnel can make a call with them. The first time this comes up, it only gets in the way, as Marcus (who isn't authorized) is trying to use a discarded link to call Security for help, but the safety checks won't let him. The second time it comes up, the link in question was stolen by someone with the skills to disable the sensor.
• Black: The first episode ends with someone trying to cut out the eyes of the late detective Han Moo-gang, who had a retinal lock on his basement door, only to be scared away when the body comes back to life. The body's new occupant doesn't realize the significance of the event until he accidentally trips the retinal lock trying to find a way in.
• Blake's 7: Discussed in "Space Fall" when Gan threatens to take off the guard's hand if he doesn't use it to open the door with a palm scan. The guard wisely agrees.
  Gan: Look, we just need the hand. If you want to stay attached to it, [grins] do as you're told.
• The Boys (2019): In "Butcher Baker Candlestick Maker", Lamplighter uses his still-valid palmprint to get Hughie into the Vought Tower, only to burn himself alive. There's then a squick-inducing scene where Hughie has to break a bottle and use the jagged glass to hack through Lamplighter's charred wrist so he can continue using the hand to rescue the people he's after. It even leads to an amusing dialogue when Hughie later uses it to open a cell door:
  Donna: Is that a human hand?
  Hughie: Yes. Yes, it is... Come on, we gotta go.
• In the fourth season of Burn Notice, it's Lampshaded, when Larry laments that he doesn't have a bone saw with which to remove the dead Brennen's left hand.
• Castle: In "In Plane Sight", Castle and Alexis use the thumb of the murdered air marshal (still attached to his body) to unlock his cell phone.
• The paintball game show Crossfire had one "mission" to steal a handily tanked "eyeball" to use on the enemy base biometric scanners. Since on at least one occasion, the entire team were wiped on that mission, the host had a tank with his gran's eyeball in — "because who could refuse a little old lady access?"
• In series 5 of The Crystal Maze, the contestant had to place a dead man's hand on a palm reader to open a safe.
• In Dark Angel, a man got both his eye gouged out and his hand cut off (on two different occasions by the same guy) so that the maiming guy could get into two different high-security installations after he had gone rogue from the evil corporation he used to work for.
• Doctor Who: Downplayed in "Resolution", in which the villain kills a security guard and drags his whole body over to a door to use his fingerprint to open the lock, without chopping anything off.
• Subverted in Dollhouse. Sierra infiltrates the National Security Agency by knocking out a female NSA worker and stealing her identity. She also takes a high-resolution photograph of her eye, which is then copied onto a contact lens.
• Farscape: The controls to D'Argo's ship Lo'la are bio-locked so only another member of the Luxan species can operate them. During an emergency Chiana (a Nebari) works out that if she coats her hands in D'Argo's vomit it will fool the sensors and let her operate the controls. In a later episode, D'Argo pre-coats the controls with his bodily fluids before letting John Crichton borrow the ship. Crichton makes sure to wear gloves the entire time.
• Subverted in Fringe in the season 5 episode "In Absentia". It's set up that the team will need to use a captured guard's retina to enter a secure building, and Walter asks for a scalpel and a spoon, and we return from an act break to see him cutting into a removed eyeball, accidentally botching it, and then asking Astrid for another. As it turns out, he had a jar of preserved pig's eyes lying around and can forge the retina pattern into them.
• The pilot episode for the proposed TV adaptation of Global Frequency inverts the usual crisis — while storming a secret prison, Miranda Zero is completely prepared to get past the retinal scanner, but runs into trouble when it turns out to be a password-protected scanner.
• Halo (2022): After Dr. Halsey is placed under house arrest and her research lab handed over to her daughter Miranda, she arranges for her daughter to visit so she can reconcile with Miranda. Then it's revealed her Held Gaze during this reconciliation was just so she could use specialized contacts to capture an image of Miranda's eyes for the retinal scan. Once Cortana hacks through the UNSC firewalls, it allows Halsey to monitor Miranda's experiments from her room.
• A variation in The Head. In episode two, the investigation team trying to find out why the winter team of an Antarctic research station were murdered are shown pressing several mobile phones against the fingers of each corpse until they find the right fingerprint to unlock them. The one phone this doesn't work on turns out to have high-level encryption, further adding to the mystery.
• In the pilot of Helix, knowing his own subdermal RFID chip has been deactivated, Peter Farragut, a research scientist infected with The Virus, kills and maims a member of his research facility's security team, severing his lower arm in order to obtain a valid chip and access labs containing other researchers. All the better to carry out The Virus's behavioral imperative to infect others.
• Himmelsdalen: Despite them boasting that their security system is airtight, the sanitorium staff apparently saw no issue with leaving identical twin sisters together, such that one of them could walk out impersonating the other. It turns out they did have fingerprint scanners, which would stop this (since twins have different ones even when identical). Siri made a cast of Helena's fingerprint though and used that to escape.
• The husband of Ilsa Pucci from Human Target was killed for his eye, so his lawyer could get into a biometrically-sealed vault to steal his identity.
• Imposters: Jules gets the Doctor's fingerprints off a glass and with Max she makes casts of them he uses when impersonating the Doctor to empty his safety deposit box by getting past the handprint required this way.
• In From the Cold: In a very unusual example of this, Jenny copies the palm print of a club owner by using her body morphing power, therefore copying her hand into his form temporarily.
• Discussed in Intelligence (2014). Leading a VIP tour of Cyber Command's facility, Lillian is asked about security measures and points out that you get in and out via handprint scanners. The bureaucrat suggests hands could be cut off, prompting this exchange:
  Lillian: Susan, the question you should be asking — "What happens if the user gets their hand cut off in a freak gardening accident?" Well? Agent Jameson.
  Jameson: Yes, ma'am?
  Lillian: Let's do a hand count today. Make sure everyone has two.
  Jameson: [completely straight-faced] Hand count. Two per. Yes, ma'am.
• In Jekyll, Hyde is obviously a bit gleeful about this one—to the point where he puts the victim's severed thumb in a lunch box and abruptly presents it to a passing scientist:
  Hyde: Give this to Dr. Gilligan.
  Scientist: What is it?
  Hyde: [smiling] He'll recognize it.
• Kessler (a 1981 spin-off of Secret Army) has the title character informing his fellow Nazi war criminals in South America that they can't access his Swiss Bank Account by cutting off his hand, as the system only works with a living hand.
• In one of the Lexx movies, Giggerota ripped off Stan's hand so she could pilot Lexx without him. The former Shadow brains provided the voice.
• The Mandalorian. In "The Prisoner", the Mandalorian rescues said prisoner only to be locked in the man's cell by his colleagues. As he still has all his equipment, he uses his grapple to grab a passing security droid and rip its arm off, which he then uses to unlock his cell from the inside.
• The Mentalist: In "18-5-4", a brilliant mathematician is shot and killed by a clown who cuts off his ring finger and later uses it to open the biometric lock on a hidden safe in his house.
• The MythBusters tested biometric fingerprint scanners, including a top-of-the-line model which was supposed to read body temperature, salinity, and electrical current, but they all proved very easy to fool.
  • To wit: One of them was fooled by a black-and-white computer printout of the finger in question (that had been licked to cover salinity/perspiration).
  • They also found that the expensive reader sold to be used as a door lock was easier to fool than the cheap one used as a log-in device on a laptop. At least, that was the perception the hosts had; they apparently forgot that by figuring out how to pass a basic fingerprint lock, they'd already overcome perhaps the biggest obstacle of the biometric fingerprint scanner (namely, the "fingerprint" part)—at that point, the only obstacle to overcome was the "biometric" part of it, which turned out to be the easier task.
• NCIS has used this a few times.
  • In "Twilight", terrorists get around a fingerprint-based biometric login for a drone controller by killing one of the authorized users and cutting off his index finger.
  • In "Power Down", Gibbs and the team learn that the NSA had the developers of the iris scanner implement a backdoor for their own access, meaning two agents have access to every iris scanner in the world (including NCIS, much to Gibbs' concern) and merrily go around clandestinely helping allied agencies with their operations. Sure enough some bad guys find out about this, capture one of them and force her to provide access for a break-in.
  • In one episode the Port-to-Port Killer leaves an eyeball in an ice cube in Tony's drink at a bar. On a hunch, Jimmy brings it up to MTAC, and the door opens, indicating that whoever the eye belonged to, that person is authorized to enter MTAC. We later see the eye's owner, alive and well, just with an eye patch.
  • Once biometric options for phones became prevalent, this tended to show up when a victim's phone is locked and password brute-forcing now runs the risk of destroying its contents, such as one which Kasie had a hunch on and used the victim's corpse to unlock the phone via facial recognition. Everyone is notably unnerved by this.
• The Outer Limits (1995). In "The Light Brigade", a character is revealed to be an alien spy surgically altered to appear human, who killed and replaced a human prisoner-of-war who was then repatriated. He mentions that the retinal scans were the most difficult to fool, so the aliens had to surgically implant him with the eyes of the man he's impersonating.
• The Punisher (2017): After killing a guy, Frank Castle uses his dead hand to unlock his phone. He can be seen later unlocking the same phone with the guy's cut-off finger, which he then dumps in a drinking glass for his friends to find. A waitress who was abused by the dead guy says it would make her day if Castle cut off any other bits.
• In the Red Dwarf episode "The Inquisitor", Lister and Kryten are replaced by another Lister and Kryten, who are subsequently killed (and blown up). Lister uses other-Lister's severed hand to open a door, leading to the exchange quoted above.
• Star Trek:
  • Star Trek: The Next Generation:
    • In "The Hunted", Roga Danar, a genetically engineered Super-Soldier, gets around the fact that the commbadges are keyed to fingerprints by knocking out a guard and using his finger to activate it.
    • In "The Most Toys", Data tries to do this to Kivas Fajo, only to find his captor is wearing a personal forcefield.
    • In "Brothers", Noonien Soong summons Data to his home using a homing device. Under the control of the device, Data had locked down the Enterprise-D. In order to beam to Soong's home, the Enterprise crew use some tricorders and fancy programming to convince the transporter that it is beaming a few Commander Datas to the surface.
    • In "A Matter of Time", a time traveler from the past with a stolen time machine from the future (got that?) tries to kidnap Data. Since his handprint is required to open the door, nobody has been able to get into or to even scan the inside of the craft. Once the time traveler learns that he can't incapacitate Data (due to his stolen phaser being disabled), Data subtly but effectively convinces him to give himself up.
      Data: I assume your handprint will open this door, whether you are conscious or not.
  • In the Star Trek: Deep Space Nine episode "Who Mourns for Morn?", a member of a criminal group that had performed a heist years ago threatens to do this to Quark, needing his thumb to sign for delivery of a package (containing the stolen money). Another member of the group points out that they can't very well expect to be taken seriously if they use a severed thumb to sign the invoice.
  • In the Star Trek: Picard episode "Et in Arcadia Ego, Part 2", Jurati reluctantly yanks out Saga's good eye so she can gain access to Picard's locked room.
• In the Supergirl (2015) episode "The Darkest Place", Cadmus steals some of Supergirl's blood (via hypodermic syringe) so that they can use it to break into the Fortress of Solitude, which is simultaneously bloodier and less violent than other uses of the trope.
• Threat Matrix has a related example when an Israeli agent attempts to frame a Palestinian agent for a hit by wearing the dead man's fingers. In another episode, Vila gets around a scanner by doing the lifting fingerprints trick.
• Torchwood:
  • In "End of Days", with Capt. Jack. He's not killed for it, but it's revealed after Owen kills him that they need his retinal scan to okay the use of the Rift Manipulator, so they hold his corpse up to the scanner. Like always, Jack gets better.
  • In Torchwood: Miracle Day, Jack and Gwen use non-invasive methods to get the biometric data from their target... the assassin chasing them, however, is a little more pressed for time. Bonus points for needing both a hand and an eye. The tissue in question is immortal and thus still counts as alive, ripped off or not.

Tabletop Games

• Shadowrun. This is noted in The Neo-Anarchists' Guide to Real Life as a way to fool biometric security devices (such as doors and credsticks). Unfortunately, the devices' designers have figured this out and altered the devices to check and see if the body part being used is still alive and attached to a body. Until they have a way to make sure the body part is attached to a conscious body, all they've done is add a bit more work.
  • And, of course, in the name of escalation, runners have figured out ways to crack the biometrics that don't require knocking out and/or maiming the target. Cybereyes that can adjust to match retinal scans, chemical baths that can reproduce a finger or palm print from a few cells, Adept powers that allow for vocal mimicry..

Video Games

• Afterfall: Insanity features a hospital mission where the retinal and fingerprint scans of two doctors are required to end a security quarantine. Guess what you have to do when your enemies are insane and dual-wielding any melee weapons they can find? Fridge Brilliance occurs when it's revealed the main character is just insane — there are two "insane" doctors who jump out when trying to retrieve the body parts. You just kill them and take theirs instead.
• Used in the 2008 Alone in the Dark game in the museum, where you need to use a sword to hack off a guard's arm to get past a scanner. It's all right, he's already dead.
• The 2005 FPS Area 51 had one puzzle be solved by picking up the severed hand to a guard and placing it on a scanner while you hit the other one. Later, you had to pick up a severed head to get through a retinal scanner.
• Batman: Arkham Knight: While on Simon Stagg's airship, Batman uses the Batsuit's tech to digitally mimic Stagg's fingerprints, allowing him to bypass biometric locks.
• In the flash series Being One, on your way to escape the lab you're held in, you have to scavenge blood samples and sometimes whole organs to get past the security robots.
• In Beneath a Steel Sky, you have to change your fingerprint to get through a fingerprint scanner.
• In BioShock Infinite, Booker and Elizabeth reach the gate of Comstock House, only to find that the security scanner at the gate requires Lady Comstock's handprint. Because Lady Comstock is dead and perfectly preserved within an airtight coffin, Elizabeth decides to break into her tomb and hack off her arm — though she also makes it pretty clear that this is also a form of revenge for having her imprisoned in Monument Island as a child. Unfortunately, Father Comstock finds out about this and uses the Siphon to resurrect the corpse as the Siren, a merger of a still-living version of Lady Comstock from another dimension and Elizabeth's hatred and self-loathing.
• Buffy the Vampire Slayer: Chaos Bleeds requires you to pick up a severed hand to use on a fingerprint scanner and later on a severed head for a retinal scanner.
• Dead Space 2 has access to certain areas keyed to the RIGs of a certain user. Thankfully, their corpse is usually nearby for you to hold up to the scanner with Kinesis.
• A non-violent version appears in Club Penguin, where Gary the Gadget Guy (Agent G) has a retina scanner locking his lab shut. Elite Penguin Force reveals that the scanner in fact is programmed to detect his glasses, meaning that anyone with an old pair of them can simply wear those and unlock his lab, which the Sports Shop clerk happens to have. You use those while looking for the missing Gary.
• In Danganronpa Another Episode: Ultra Despair Girls, in order to get past a retinal scanner in the Towa Group's headquarters, Komaru is forced to use the severed head of president Takuichi Towa himself.
• In the ending of Descent 3, the Material Defender uses the hand on Dravis's corpse to deactivate the robot virus.
• The Doom Slayer in Doom (2016) has to bypass several UAC biometric locks by using the appropriate body parts from deceased employees with the right clearance. The game lampshades this in the interface when he uses someone's upper torso to access the BFG weapon vault. There's a subversion hiding in there, too; the BFG's storage chamber has another biometric detector that checks for the entrant's vital signs, and the Slayer's mismatched readings set off the room's security countermeasures.
• The Duke Nukem game Land Of The Babes makes you pick up an enemy's head to get past a retinal scan.
• In WARP Software's Enemy Zero, one of the items Laura Lewis collects is a hacked-off pair of fingers, which she uses to bypass a DNA scanner.
• Used straight in Fallout 2 in an abandoned Military Base. Retinal scanners operating locks in various sections of the base require specific eyes to unlock.
• A variant in Final Fantasy XIV. As a descendant of the Allagan royal bloodline, G'raha Tia has the ability to bypass the security locks in Azys Lla. In the Patch 5.5 story quests, he gives you a "spirit vessel" containing his blood in order to test whether simply having his blood on hand will allow you to pass the Allagan biometric check. Conveniently, it works without a hitch. This may have been by design. A number of the places with such security were workplaces for individuals not of royal blood, so having to bring royalty to work to unlock the door every time would have been inconvenient.
• Ghost Recon: Future Soldier: In the mission to rescue the captive Russian president, Kozak needs to get past a retinal scanner. He manages to catch a Russian soldier off-guard, uses them to activate the scanner, then knocks them out.
• A pair of doors in Pandora's Temple in God of War are locked with the heads of the architect's sons.
• Hi-Fi RUSH: Near the end of stage 7, "The Climb", Chai ends up having to drag a half-conscious Korsica out of her office, and at one point mashes her face against a retina scanner to get through a door.
• Hitman:
  • Subverted in Hitman: Absolution. The biometric scanners you run into are state-of-the-art. Not only will using a dead enemy not work, but forcing a hostage's head into the scanner will ALSO fail, since the device can detect (presumably via pupil dilation and rapid eye movement) that they are under duress. The only way to trick a scanner is to either use disguises to trick an authorized person into opening it for you... or just go hack the computer controlling the scanner, and register yourself as authorized. The password's probably on a sticky note attached to the monitor.
  • Played straight in Hitman (2016) in the Colorado stage, where the biometric lock requires target Sean Rose's face, meaning that you either get the man himself to open it or you use a 3D-printed mask.
• I Was a Teenage Exocolonist: In the Array plot, Vace decapitates Noctilucent's head and uses it to unlock the door to the Convergent Domain, where the Array is housed.
• KOJOUJI: At one point near the beginning of the game, Mr. Scott finds a dead guy being eaten by a giant worm. After avoiding the giant worm's attack, he can pick up the dead guy's hand, which is useful in that it can allow him to get through certain doors.
• Markus from Last Half of Darkness: Beyond the Spirit's Eye cut off his best friend's finger after killing him, and you must retrieve the severed digit to enter the deceased friend's lab.
• The Legend of Zelda: Tears of the Kingdom has a rare consensual example. Due to Gloom damaging Link’s right arm beyond repair, the spirit of the Zonai Rauru takes his preserved arm and grafts it onto Link to prevent the Gloom from completely destroying him. Due to Link now having a Zonai arm (one with Rauru's clearance, at that), he can activate various Magitek hand scanners that have been spread around the world since The Upheaval.
• The combination of glass eye and retinal scanner also pops up in The Longest Journey.
• A low-tech version in Manhunt 2; in order to enter a heavily guarded club, Daniel has to cut off a guard's head and hold it up to the peephole on the door. The doorman will let him in thinking his colleague is still alive.
• Mass Effect 2: In the From Ashes DLC, a DNA sample is one of the things needed to get past the biometric lock on the vault that Shepard and Kasumi are trying to break into. They succeed in finding it by searching the bedroom of the target rather than by taking a piece off him.
• A low-tech variant comes up in the first Max Payne game when Max needs to gain access to a laundry that's being used as a front for drug dealing. After failing to talk the mook on the other side of the door into opening up (mostly because he can't resist being a smartass), he grabs a junkie who's loitering nearby and is apparently a customer in good standing and sends him in to have a go. At gunpoint.
• Metal Gear
  • Subverted in Metal Gear Solid 2: Sons of Liberty: it's stated up front that the retinal scanner in the Shell 1 core can't detect dead eyes, so the player has to drag a guard to the scanner and mash his face into it.
  • Used in a more comprehensive way with the football. The nuclear launch codes in the presidential briefcase require the President's complete biometrics and are able to detect deviations from the expected readings, thereby preventing any agency from coercing him or using removed tissues. President Johnson willingly activated the nuclear weapons on Arsenal Gear because he wanted more power than the Patriots allowed him and Ocelot killed him in retaliation.
  • Played straight in Metal Gear Solid 4: Guns of the Patriots. Old Snake had to take a dead soldier's gun, and since the gun only reacts to the soldier's nanomachines, Snake had to bleed the soldier out over the gun so he can use it.
  • You can either cut off a mook's left hand and use the data stored in it to open a gate in Metal Gear Rising: Revengeance or just cut the locks open with Raiden's Absurdly Sharp Blade.
• A curious aversion in Metroid Prime 3: Corruption. Samus routinely has to press her hand on various scanner switches in order to activate them, and her normal hand works just fine even for scanners of different species. It makes sense that she can activate Galactic Federation scanners (with human handprints) since she works for them, and somewhat sense that she can activate (four-fingered) ancient Chozo scanners since she is part-Chozo, but then she can also activate (three-fingered) Space Pirate scanners just the same. It's never stated if the Powered Armor she wears is hacking the scanners or performing any other bypass.
• Path of Exile uses a fantastical version in Act 5. The sanctum of the Templar order is protected by the power of the god Innocence, and only those who "see with the eyes of true faith" can enter. Fortunately one of the High Templar's inner circle is nearby and fighting to put down the slave rebellion the player has joined. Your quest-giver tells you to pluck out Casticus's eyes after killing him and the good Justicar will "see" you through the wards.
• In the Big Bank heist in PAYDAY 2, one step in sneaking through the Benevolent Bank's security concerns bypassing a thumbprint scanner. Bain has somehow acquired a disembodied thumb (whose model happens to be far larger than any other model's thumbs) and doesn't bother explaining where he got it.
  • Averted in the Hoxton Revenge heist. If the panic room has a retinal scanner, and the FBI boss happens to be killed, then the stealthy part of the heist goes out the window, as the scanner needs an eye with a pulse.
  • During the Boiling Point heist of the Hardcore Henry DLC, the scanner has a chance to require the lead scientist's handprint. Unfortunately, the lead scientist is a little on the dead side, having been Impaled with Extreme Prejudice on some rebar. Still, you only need his hand...
• PAYDAY 3: Retinal scanners appear as reoccurring security measures, which must be bypassed by taking a hostage with clearance and pushing them in front of it. Said hostage must be alive in order for this to work, however.
• In Penumbra: Black Plague you get past several security scanners like this, using blood to enter the kitchen, then a hand and head to enter the library. Interestingly, one door that leads to the cryogenic freezer has a hand scanner that when you try to scan the hand you have already procured at this point, tells you that the person whom this hand belongs to is in critical condition and will not accept it.
• Activating The Persistence's Stardrive is only possible for the ship's dead captain. Your final goal in the game then is to steal her DNA, clone her, and occupy her body to trick the ship into thinking you're the captain.
• Predator
  • Averted in Predator: Concrete Jungle, where scanners require a scientist to unlock. It's unknown if the predator could just rip off the heads since he is strong enough to simply drag them to the scanners and ram them in hard enough to kill them while opening the door.
  • But played straight in Aliens vs. Predator (2010) where the Predator has to use a severed head to open several doors with retinal scanner locks.
• Used in Prey (2006), with a severed alien hand which gets progressively mankier throughout the game.
• True to their nature, the protagonists in the [PROTOTYPE] games don't just settle for the necessary body part, opting to instead consume their target entirely and then just turn into them when necessary.
• Quake II has a locked door, with the item required to open it being a Commander's Head. You get it from a medical lab where a Tank Commander is undergoing surgery.
• Rain World has Artificer, who has a singular grudge against the entire Scavenger species. Her violent nature has locked her Karma at the lowest level, and this would normally prevent her from advancing further past the Karma Gates... except that the Karma Gates apparently can't differentiate between living and dead sources of Karma, and Scavengers have Karma ratings. So the ideal method of bypassing the gates is to find the most morally ascendant Scavenger on the map, assassinate them, and drag their corpse to the Karma Gate to get through befoe it starts stinking too much and loses its Karma value.
• In Resident Evil 4, after Chief Mendez dies, his false eye pops out, whereupon Leon scoops it up and puts it in the scanner. If you examine the glass eye (probably because you're wondering why in the heck a retinal scanner can read it), you learn that the glass eye has an encryption pattern on the iris, which is what the scanner reads.^note Which makes perfect sense when you consider the highly mutagenic nature of the stuff the bad guys are playing with: retinas are probably not the same after being exposed to Las Plagas, so they use an immutable object, i.e. the glass eye.
• During Issue #7 of The Secret World, the player ends up trying to break into an Orochi research facility hidden under the Transylvanian forest — only to be kept out by a biometric lock requiring both a palmprint and a retina scan; thankfully, there are plenty of dead Orochi security guards strewn about the area, allowing you to collect the necessary... components... with ease.
• Shadow Man has a variation on this in the prison level. It's actually a keycard scanner, but the card in question is being held in a death grip and can't be removed without taking the hand.
• During the "Demon Trafficking" sidequest of Shadow Warrior 2, Larry, Lo Wang's demon gun dealer, tells him that the Yakuza sex traffickers that Wang wants to rescue some demons from are holed up in a compound that requires a retinal scan. Wang lampshades this by asking "Are you saying the entrance fee is one dead Yakuza head?"
• This is a solution to get to the shuttle bay and steal a shuttle in Space Quest VI: Roger Wilco in the Spinal Frontier. The shuttle bay entrance is guarded by two security guards, who won't let Roger inside. After knocking them out, Roger realizes that both buttons have to be pushed simultaneously in order to open the doors. He goes to the ship's android Lieutenant Commander Circuit Sidney and asks to borrow his arm. After using his own arm and Sidney's to open the door, he realizes that the shuttle can only be started by an authorized crewmember, which Roger (despite being an Almighty Janitor) isn't. He goes back to Sidney and asks for one of his eyes (why a senior officer would give his body parts to a janitor without explanation is not explained), which he uses to fool the shuttle's retinal scanner.
• Likewise in Splinter Cell, though you need a breathing, conscious person for the retinal scanner, as the scanners can tell if they're living or dead.
• Strife has a very early example where you need to get through a hand scanner-locked door to complete the mission, but the person whose hand is necessary is not at all feeling cooperative. The solution? Kill him, and his bloodied, severed hand will drop as an inventory item for you to use to get through the door. Your Mission Control partner will comment on this brutality.
• Used in the original System Shock, where you can use the entire head of an (already-dead) officer onboard the ship to reach an optional area. The door is locked via retinal scanner, so you need to look around the level for a head whose eyes are relatively intact.
• Tales from the Borderlands:
  • The characters are faced with a retinal scanner that requires the eye of General Pollux, whose body happens to be in a case nearby. When they find that he's wedged in too tight to move over, Fiona is forced to use a spork to gouge out an eye and accidentally destroys the first one after being startled by Rhys. Upon activating the scanner, they get a pre-recorded message from the General himself in which he states that he's going into suspended animation and asks anyone who is seeing this to activate the revival protocol. Cue silent horror from the characters as they look at the now-eyeless Pollux...
  • Fiona will keep the General's eye for the rest of the game, and you can even use it again! Doing so will freak out your mercenary companion Athena, which is impressive as she's been through this sort of thing before.
• At one point in Technobabylon, you have to access a computer locked with a palm print. The owner is already dead and in numerous pieces, so getting his hand is easy. However, the scanner is sophisticated enough to tell living flesh from dead flesh despite its age, so you need to figure out how to fool the scanner into thinking the severed appendage is alive.
• Particularly cruel twist occurs late in Tormented Souls when the protagonist Caroline Walker has to access an underground bunker that is locked by two retinal scanners situated on each of the sides, therefore intended to be used by twins. Caroline ends up getting around this by traveling back in time through a VHS projector to when she was unconscious in a bathtub and scalp her own eye, then hooking it up onto one of the scanners.
• The non-fatal version is used for a bit of mood-lightening comedy in Transformers: Fall of Cybertron. After cornering and defeating the Insecticon Hardshell, Grimlock reaches into the turret that Hardshell had been using and drags the Decepticon out, bashing him about before smashing him facefirst into a wall... whereupon the scanner there cheerfully accepts that bit of violence as Hardshell's access scan and opens the door. At least Hardshell got to keep his head—Sharpshot wasn't quite so lucky.
• Warhammer 40,000: Rogue Trader: The vault holding House von Valencius's Warrant of Trade needs a blood sample from a member of the dynasty to open. Since the player character is a newly discovered von Valencius scion, Kunrad Voigtvir captures them and forces them to open the vault in the beginning of the game (and Kunrad is too corrupted by Chaos to open it himself). Fortunately, the security sentinel detects stress "humors" in the blood sample and asks the PC if they need assistance—which it provides in the form of a pair of Sentry Guns that promptly hose Kunrad's followers down with lead.
• Averted in Watch_Dogs 2. Tidis' biometric palm readers check heart rate and blood flow, meaning using severed or "coerced" hands isn't viable. This necessitates using a Tidis robot to set off an EMP in the security hub and reset the doors to the default codes... a plan Wrench is significantly against, as the only Tidis robot Dedsec has is Wrench Jr.
• Xenogears: When Bart's enemy Shakan learns that the "Fatima Jasper" needed to unlock the Fatima Treasure is in fact the brilliant blue-green eyes possessed by members of the royal bloodline, he exhumes the bodies of Margie's parents and plucks out their eyeballs. It's kind of hard to call this Kick the Dog since this character can't walk two feet without punting a puppy. But that doesn't mean it's not incredibly satisfying to beat him in the Boss Battle.
• In ZombiU, part of the final mission involves tracking down the zombified Dr. Knight so you can use his eye to get past a retinal scanner.
• Sharp from Zombie Infection wakes up in a top-secret government lab after he passes out, where he then punches a random scientist out cold and drags the guy to a fingerprint-coded locked door.

Webcomics

• The Adventures of Dr. McNinja: "Allow me to perform a simple amputation, and I'll be right back." Subverted in that the dinos have figured that trick out. So they have to do something different. Also parodied in the Alt Text: "As they move through the fortress, they continue to find obstacles that can only be solved by going back and retrieving other body parts from the guards."
• An unusual example in Freefall, in which Sam, being an alien, needs artificial fingers to use human fingerprint scanners; he keeps them on a keychain and lets Florence borrow it at one point.
• Subverted in Power Nap: Drew takes Cornelius's head (which was previously severed) and carries it on the train in a trash bag, in order to get through the security in his apartment building... only to find out it's a slummy place with no retinal scanner.
• Suggested, though not actually used in Schlock Mercenary during the CSI parody arc.
• S.S.D.D. does the "heroes late to the massacre" variant twice; once with a severed head and retinal scan, the second time with a finger.
• In this Team Fortress 2 comic, the Heavy needs to get past a handprint scanner to get into the Administrator's secret base, so he elects to use a recently-deceased Mook's severed arm.
• Cat Girl Naveed uses this in Zap!, during her breakout from a maximum-security prison. Access granted, Mr. Stevens...

Web Videos

• Apparently Hadriex went through all the trouble to build a hand scanner... That accepts glove prints. Presumably they won't wake up to find their hands missing anymore.

Western Animation

• Referenced by Pam in "El Secuestro" on Archer. She asks how the kidnappers expect to get past the biometric security, mentioning that if they killed her the only way would be to cut out her eyes and chop off her thumbs. She tells them to not be dicks, and leads them straight to the ISIS offices.
• Subverted in Family Guy. Peter, Quagmire, Joe, and Cleveland are trying to break in to Carter's vault to rob him. When voice identification is required, Cleveland successfully mimics Carter's voice. When penile identification is required for the next door, Quagmire just sticks his penis in and breaks the scanner.
• Futurama: In "A Clone of My Own" the crew uses an entire bucket of Cubert's blood to trick the Near Death Star guards into thinking Fry is Prof. Farnsworth, whom Cubert is a clone of. The guards complain that a few cells would have been sufficient.
• In Get Ed, a robotic assassin dispatches several Mecha-Mooks, but when it tries to use one's arm to open a container, it turns out that only works when the arm is attached to a body that gives it power. So it pops its own arm off and attaches the other robot's arm to itself.
• Harley Quinn (2019): Doctor Psycho uses his telekinesis to grab a security guard and hold him against a retinal scanner.
• In Regular Show's "The Dome Experiment" episode, Benson knocks out one of the dome scientists and places his teeth onto the second dome's dental lock, opening up its main doorway and allowing Benson to enter it and investigate it further for clues as to what's really going on with it.
• Unusual example in Sherlock Holmes in the 22nd Century: rather than cutting them off, the thieves cloned thumbs and eyes to fool scanners. This wouldn't work in real life, because neither retina patterns nor thumbprints are based on DNA.
• In the Star Wars: The Clone Wars episode "Rookies", Captain Rex, Commander Cody, and three rookie clones are trying to break into an observation outpost that has been captured by commando droids as a cover for an invasion fleet being led by General Grievous. In order to get in, Captain Rex approaches the front door and asks to be let in deliberately altering his voice to sound like a droid. Being infiltrators, the droids are smart enough to ask Rex to remove his helmet and prove he is a droid. Rex ducks out of frame of the camera and then holds up the severed head of a commando droid to fool them into opening the door.
• In one episode of Stroker and Hoop, Stroker sneaks into a high-security facility and finds he needs to pass a handprint scanner. No problem, just drag the guard he knocked out a minute ago over and put his hand up to it. Then he has to pass a urine sample scanner. Uncomfortably, he uses the guard to get past this, too — only for the next guard he sees to pull a gun on him as he walks by, having seen the whole thing over the security cameras.
• In the Transformers: Prime episode "Alpha and Omega", Megatron has his right arm replaced with that of a deceased Prime, so he can use the Forge of Solus Prime, which could only be wielded by a Prime.
• An episode of The Venture Brothers has Brock and Shore Leave use a severed hand and a severed head to infiltrate a lab as part of a SPHINX mission.
• It's fairly common practice in Voltron: Legendary Defender to use severed arms and hands of Galran Mecha-Mooks this way on Galra technology. That is, if Shiro's artificial arm isn't available. Keith is able to use this technology with his own hands, foreshadowing that he is part Galra.

Real Life

• Averted for the iPhone 5s print scanner. It is designed to read only living tissue. If someone were to lop off someone's thumb, the device would not be able to read it, and the effort would be in vain. Unless the person managed to attach it to someone else and kept it alive. Better details here.
• Until someone realized that a living tissue could be under the dead one, or, in a less grim example, a latex print of the target's fingerprint they got off a glass and even build from pictures alone. Even licking the false print is enough sometimes.
• Kieran Higgins registered his severed fingertip to unlock his Samsung Galaxy phone, claiming it works for the purpose even though it was crushed, preserved in medicinal alcohol (of course, he dried it before actual use), boneless and has a hole going through where its bones were. The fingertip was detached in a crane accident.
• Some Android phone manufacturers (most notably Samsung) have attempted user authentication by facial recognition. Unfortunately such systems could be defeated with the use of masks or even photographs! The iPhone X attempts to avert this problem by using a 3D facial scanner and attempts to distinguish living faces from masks by looking for facial twitches, etc. While one security researcher claims to have defeated Face ID using a sophisticated mask, its effectiveness is moot as it requires a precise model of a target's face. Face ID was also notably susceptible to identical twins and close relatives.
• Scarily enough, real-life criminals know ways they can get your fingerprints off beverage containers and similar surfaces you've touched and use them for all sorts of ill purposes, including framing you for their misdeeds! There are ways to distinguish faked fingerprints from real ones; however, investigations generally don't employ tests that refined unless the police have other grounds to suspect such forgery. Not to mention most criminals are petty criminals and won't go through all that effort and/or are not smart enough to do so. It's a lot easier to just smash the case and wear gloves.
• Some high-end vehicles sold in nations where carjacking is a serious problem require a fingerprint to start the vehicle. Early versions of these systems didn't confirm the finger was alive, leading criminals to the obvious solution to stealing such a car. As the Wikipedia article rather delicately puts it:
  If the item is secured with a biometric device, the damage to the owner could be irreversible and potentially cost more than the secured property. For example, in 2005, Malaysian car thieves cut off the finger of a Mercedes-Benz S-Class owner when attempting to steal the car.
• The James Bond example mentioned in the film section above is actually Truth in Television. As early as the 1970s, surgical procedures were developed by the United States military to alter a person's retina. Why? It was to duplicate someone's retinal patterns for retinal scans.
• The Irish-American gang The Westies were reputed to refrigerate the severed hands of people they had killed, so they could plant their fingerprints on murder scenes so the police would be hunting someone who was actually dead.
• The fact that this trope can happen is why really secure security systems go for multi-factor authentication — you can't change your thumbprint if someone finds a way to copy or emulate it, but you can change passwords.

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