Extracting resources from the bodies of living, dead, or dying people. "Extracting resources" is usually as visceral as taking organs from the living, though sometimes as vague as harvesting "Life Energy". It is common for the bodily integrity of the donor/victim/walking resourcebag to be transgressed: there is a strong horror theme. There are a few exceptions, such as reclaiming water from the dead in Dune, which is played as a religious and cultural practice.
Sometimes a particular group is preyed upon; criminals, the homeless, and disposable sex workers are popular for this.
There are many subtropes, although a lot of them can also be applied to non-humans:
In Puella Magi Madoka Magica, Magical Girls are harvested by an alien race for their souls, which are used to stave off universal entropy. The MG's themselves are sent to kill corrupted, "harvested" husks of former MG's, called Witches, and if they don't die in battle, will fall into despair and become Witches themselves. Yes, it's as bad as it sounds.
It is implied in Macross Frontier that the dead are recycled for their organic biomass. This would be understandable since the show takes place on a colony ship, where resources are non-renewable. However, this seems to only apply to civilians. Military personnel are exempt and are given a more conventional burial.
On top of this, the Macross universe had Earth get bombarded by particle weapons which resulted in the near-extinction of the human race and the apparent loss of a huge amount of biomass to judge by the color of the planet seen from space. At this point, fifty years later, recycling everything seems to be as much an accepted fact of life as indoor plumbing is today.
Tower of God - Ja Wangnan has run himself so much into debt that he could never hope to repay, but his Loan Sharks give him one last chance: they'll pay for the next test he'll take, but he will have give up all his organs if he fails. So it really is a matter of life and death to him. Luckily, he meets Viole.
And, that's nothing in comparison to what the Workshop does to acquire living, walking and talking ignition weapons. The casualty rate amongst the lucky chosen experimental groups of children is... a little excessive, shall we say?
Kaiba has the utopian planet of Apiba. As the planet serves as a massive body trading zone, the countless discarded bodies are collected and converted into free food.
In Cannon God Exaxxion, the corpses of dissenters against the Alien Invasion are carted off to processing plants to be converted into either raw biomass for industrial bioengineering or food.
The Big Bad of the manga Uzumaki is an enormous ancient city. Though alive, its only instinct is to continually grow bigger, and it finds absorbing humans to be the best way to do so. Later in the manga, once people begin to turn into snails, they quickly end up as a food supply for the other survivors.
In the end of the manga/Brotherhood, Father eats the souls of all the people in Amestris and then uses that power to eat God himself...until Hohenheim reveals that he's been derailing Father's plan for years and activates a countermeasure that rips all the Amestrian souls out of Father and restores them to their original bodies.
The 2003 anime one-ups this by revealing that all alchemy is powered by souls from an Alternate Universe (ours), shunted into Amestris through the Gate of Truth. The reason alchemy had been growing in potency lately was because our world was undergoing World War One at the time, providing the alchemists with lots of power.
Revealed as a major plot twist in Adieu Galaxy Express 999. It involves the literal nature of the Ghost Train (It transports recently dead people.) and the source of the energy capsules consumed by humanoid machines (Their bioenergy is extracted in a huge plant.).
The Big Bad in Van Dread is Earth, coming to harvest all the colonies for replacement parts. Strangely enough, Earth isn't real efficient in their harvesting. Spines come from one world, skin from a different world, there's even planets to be harvested strictly for genitals.
The Hundred Eyes Clan in Maranosuke harvests the bodily fluids of girls via intense sex to create an immortality potion that basically reduces the victims to... it's not pretty. Those that haven't been drained can somehow be modified into custom sex slaves by Zegenshi using the same process. The real kicker, while Zegenshi used it to make himself around 500, the Big Bad was already immortal and is just harvesting for the fun of it... and Mommy Issues.
In the Rurouni Kenshin manga the puppet master Gein use corpses to build his puppets.
In the Korean WebtoonCity Of Dead Sorcerer it's implied that the sudden appearance of mana energy (magic) that muggles could use with the help of magitech was due to the mass murder of "real" magic-users, who were apparently living in secret a la Harry Potter since no one had ever heard of someone who could use magic without a dispenser (basically a wand). Sadly it seems they were exterminated with the help of collaborators.
In Magi - Labyrinth of Magic the elite Magic School and its surrounding city is powered by 200,000 muggles hidden deep underground. It's not bad as far as this trope goes: they get all the food and drink they need and don't have to work, but when their energy is used up they're tossed alive into a bottomless pit. It's hinted these muggles are descended from the nobles who oppressed the magicians in the past.
The Marvel AdventuresSpider-Man ran into this with his "smart-cloth" black outfit, which required the host's bioelectric energy to do its wearer's commands. Spidey ended up loaning it to Reed Richards to analyze, but Johnny ends up letting it loose and it runs into a disgruntled thief named Eddie Brock and voila, the Marvel Adventures take on Venom is born.
Dilbert plays this trope a lot. Once, the title character suggested using smokers going outside to have a smoke as a non-lethal power source. Dogbert also plays this trope straight when he throws activists into the furnace to power the town.
In Judge Dredd the dead are recycled after the funeral services and processed into other goods and materials.
In Grant Morrison's Seven Soldiers of Victory, in Klarion's puritan underground town the dead are risen for workforce as "Grundys." And yes, they are indeed similar to Solomon Grundy.
In the New X-Men comic a group led by John Sublime calling themselves the U-Men do this in order to gain a mutants powers, although its rarely successful. Sublime was even revealed to have a massive facility in Hong Kong with hundreds of imprisoned mutants, many of them already missing numerous body parts. Of course, Sublime never really cared how successful the process was. This was just another one of its attempts to ruin mutant-baseline human relations in a bid to wipe out mutantkind forever.
Unlike The Matrix, however, it's also heavily implied that he didn't bother to try to nourish any of his prisoners in the Egg Grapes, just discarding the ones he "used up".
In the UK's Sonic the Comic, Robotnik's plot during the buildup to issue #100 involved connecting the Emerald Hill Folk to a machine to form a gigantic Wetware CPU.
In the Strikeforce: Morituri "Electric Undertow" limited series, it is revealed that the alien VXX199 are hiding behind the Earth's Moon, where they are secretly modifying humanity so they can induce spontaneous combustions and harvest the psychic energies released.
Vandal Savage, an immortal caveman from the DC Universe, has to claim the body parts of his descendants in order to live. These have included Roy Harper and his daughter, Scandal Savage. Eventually he consumes a clone of himself. Note that Lex Luthor claims Savage invented cannibalism... and means it.
In the FIMFan FicRainbow Factory, rainbows are made out of foals who fail their flight exam. Specifically, their ribs are broken, and then they are mutilated in what is essentially a giant meat grinder.
And the less said about what Pinkie's cupcakes are made of in the infamous fanfic Cupcakes, the better.
The Danish black comedy The Green Butchers is about two butchers who start their own shop. When the new cooling unit is installed, the technician is accidentally trapped in the freezer over night. The next morning Svent find the frozen body, freaks out, and decides to hide the accident by cutting it up an selling it as chicken. When all the meat is sold, business slows down to a crawl, so Svent starts murdering people to keep his dream of his own shop alive.
Fried Green Tomatoes. As Sipsey has killed Frank Bennett on accident, Ruth and Idgie cut him into steaks and serve him to the customers in their restaurant to hide the homicide
The legend, musical and recent movie Sweeney Todd: The Demon Barber of Fleet Street all center around the idea of two people using human meat to fuel a successful meat-pie business. When Mrs. Lovett used animal or other miscellaneous meat, her business failed; only when Todd and she began using fresh flesh did she become successful.
In the film Virus, an evil computer program from outer space has taken over a research ship and wants to dissect the human characters to use their muscles, nerves, and organs to help improve its cybernetic army. This leads to a grimly funny moment when one character asks the entity "what do you want from us?", and it responds with a simple readout of all the organic components it intends to harvest from them.
Something similar happens in Quake II, where the Strogg, the evil cyborg race with whom humanity is at war, use humans for meat and as a means to create more Strogg.
In The Matrix the robots use humans as batteries! (And recycle the dead into nutrient solution to help feed the living).
This was all Executive Meddling. The original story had the brains of the humans being used as part of a neural network for additional computing power. But the suits thought that was too hard for people to understand. So instead we get them as batteries, which is a major liberty with the laws of physics, as well as a huge headscratcher - why not keep the humans sedated, and not have to waste power on the Matrix? Or just use animals?
It's not theft, it's repossession of financed goods due to contractual default. Therefore it's legalized in Repo! The Genetic Opera. But the real "Soylent Green" is the blue stuff; an addictive anesthetic used in the surgeries that remain in the body and is harvested from the dead for resale on the black market.
Zydrate comes in a little glass vial.
A little glass vial?
A little glass vial!
In the German horror flick Anatomy, dead bodies are recycled as anatomically correct medical displays. Oh and they are still alive and unable to move when they begin the surgery.
Gunther von Hagens does that in Real Life (the exposition is called Body Worlds). His methods of acquiring bodies are more civilized, however. Or so he claims.
Done in America by Bodies: the Exhibition.
In 2005's The War of the Worlds, the aliens use ground up human pulp as seed fertilizer/germination agent for their homeworld's fauna (the red weed). Before the movie is over, a good portion of New England is covered in it.
In Igor old Igors are recycled for parts at the end of their usefulness... or sometimes just because someone feels like it.
Tyler Durden in Fight Club collected human fat from the disposal bins behind a liposuction clinic, then used it to make expensive soap for rich ladies. Bonus points for fulfilling this trope, as the narrator lampshades the idea that the same women who paid to get rid of the fat would now pay him to return it.
Narrator: Tyler sold his soap to department stores at $20 a bar. Lord knows what they charged. It was beautiful. We were selling rich women their own fat asses back to them.
Waterworld does this. The bodies of the dead are dumped into nutrient vats, yellowish brine pools, as part of their burial ceremonies. They attempt to dunk the nameless Mariner in it when they discover he is a mut-o.
Funerals conducted in Theodore Rex involve the deceased having their bodies liquefied and used as fertilizer for the flowers. Mourners can take these flowers home, like taking a literal part of their loved one with them.
Arguably in Gamer where people derive pleasure by controlling others in twisted versions of The Sims and an FPS with real guns.
Lampshaded in NetherBeast Incorporated, as the senile CEO forgets he and his employees are all vampires.
Turner: I'd stay away from Human Resources, if I were you...... Ha! Human Resources! Now, that's irony!
In Escape from L.A., the Beverly Hills area is inhabited by a group of freaks who, due to undergoing too much plastic surgery, must regularly kidnap prisoners and harvest them for body parts in order to keep themselves alive. Snake very nearly ends up becoming one of their next victims.
Bonus points for the "Surgeon General" being played by Bruce Campbell.
In Frank Herbert's Dune series, Fremen reclaimed the water from dead bodies in something called the "death still". Somewhat justified because of the extreme scarcity and value of water on Arrakis. And then the Bene Tleilax, who have a tendency toward this sort of thing. Probably the best example would be the “bi-Ixians”. And the Axlotl Tanks, truck-sized bioreactors used for growing Gholas and Spice, but which are actually the female Tleilaxu. All the female Tleilaxu.
In other novels, the deathstill is used as a very painful execution device. This is how Bronso of Ix (AKA Bronso Vernius) is executed for doing exactly what Paul asked him to.
While it's generally acceptable practice for the Fremen to kill anyone caught alone in the desert (i.e. someone who would die anyway), especially without a stillsuit, deliberately attacking other sietches or groups of Fremen for their water is considered so heinous that their water is poured into the desert for fear of being contaminated.
The Igors from Discworld harvest their dead for spare parts, with some body parts being handed down from generation to generation (When they say, "He's got his father's eyes," they're not being metaphorical). Also, they offer their services as surgeons to villages on the condition that they can harvest the villagers' body parts once they die of natural causes. A village can refuse to let the Igors collect on their payment, but then they'll never offer their services to that village again. "What goeth around, cometh around. And thometimeth, it thtopth."
"The glath clock? My grandfather built it with thethe very hands!" And that was when Jeremy noticed the stitches going around Igor's wrist...
There are several Discworld-series cases of Troll Resources, as these silicon-based folks' diamond teeth are quite valuable. In Soul Music, Cliff covers most of the expenses of the Band With Rocks In out of his own mouth, and Cohen the Barbarian's din-chewers were crafted from troll teeth in The Light Fantastic. Even the non-diamond parts of a troll can be broken up for rockeries and gravel.
This makes the long-standing feud between Dwarfs and trolls very sensible. One species enjoys searching for valuable minerals, the other is made out of valuable minerals ...
Brave New World featured factories which would harvest all the useful parts of a body. Children were taught that death was acceptable and even good (the hospitals had the best toys and gave out candy when someone bit the dust), so long as society as a whole continued, so that no one was mortified that human beings were being scrapped for parts like old cars.
Early in the chronology of Larry Niven's Known Space universe, the success of organ transplanting leads to the death penalty being invoked for the most trivial of crimes (in one early story, the main character is sentenced to death by organ removal for jaywalking). The rich and powerful can literally have their pick from vast vats of organs. Particularly seen in the novel A Gift From Earth, where the threat of this form of punishment is used by a tyrannical minority to keep the workers in check, and covers up a message from Earth detailing how to create artificial organs, since this would destroy their power structure.
Clone troopers fall under this in the most literal sense, being designed and trained to be sent to fight and die in the Grand Army of the Republic. A novel in the Star Wars Expanded Universe mentions "recycling tanks" for those who are brought back from the battlefield dead, dying, or alive but not so well that they can recover easily/fast/cheaply. A surgeon, who is later horrified by how dismissive he was of them as people, idly remarks to himself that clone organ transplants are easy, with hardly any rejection. Poor bastards.
Also in the Star Wars Expanded Universe , it is mentioned that the Sand People stick straws into the bodies of dead people they find in the desert, and suck out their body fluids. Well, it's not like they're gonna need them, is it?
In the Riverworld series, every human being since the Pleistocene is reincarnated on an alien planet, on which they are the only animal life. While food is provided, lack of raw materials means that by the second book, human skin comes into widespread use as the only available leather.
It should be noted, however, that when someone dies on Riverworld, they are reincarnated elsewhere the next morning. This makes the reuse of their old bodies even creepier.
In Laura Mixon's Burning the Ice, corpses are recycled into the artificial food source called mana and eaten in a ceremony honoring the dead. The colonists live on an icy moon of a gas giant planet so everything has to be recycled for them to survive.
Norman Spinrad's Bug Jack Barron has as its main plot point an experimental immortality treatment made by subjecting children to massive amounts of radiation and then harvesting their endocrine system for a transplant. To boost Aesoptinium levels, the majority of the kids being harvested were bought outright from impoverished black families.
In some of George R. R. Martin's science fiction stories, there's a profession called a "corpse handler". What they do is control a number of human corpses linked together by bionic technology and use them to perform manual labor (forest clearing, construction, and the like).
The Innocents Abroad by Mark Twain contains a joke about the Egyptians burning mummies for steam train fuel. Unfortunately the story has been taken as true, right up to the present day. "D—n these plebeians, they don't burn worth a cent—pass out a King!"
In the Necroscope series by Brian Lumley on the world where vampiric beings originated, the various Whamphryi overlords/ladies would stage raids on the human population to collect resources for the "provisioning". They would take captured people and mix them with their own metamorphic flesh, turning them into anything ranging from battle mounts capable of flight to living plumbing systems to pipe water throughout their tower-like homes. It was mentioned in one book how they would even grow stairways for their towers out of the bones and cartilage of hapless captured people, or any underling who manged to displease them enough.
In the book The Time Traveller's Wife, Claire asks Henry, a Librarian, if the rumor that his library has a rare book that was bound in human skin is true, and he says yes. This opens things up for a great line later, when a fellow librarian tells Henry that his boss wants to see him, and that the boss "looks like he wants to rebind The Chronicles of Nawat Wuzeer Hyderabed."
The War of the Flowers by Tad Williams features the main character enjoying some pixie dust. Given that he's an aging rocker, this isn't so unusual, but he's later reminded that he's in a reality where there are actual pixies.
Another example involves how the fairies magitek works- they used to power it with belief, but since humans have become less superstitious while the energy needs of fairy society have gone up, that's no longer feasible. The new energy source involves leeching magic from living, usually lower-class, fairies, usually against their will. Though normally not fatal, the process leaves the victims burned out shells who are sickly, magic-less, and frequently insane.
In the Deathstalker series Valentine Wolfe used this at one point. He harvested certain chemicals from the bodies of humans razed when the Empress burned Owen's homeworld. He then used these to produce a highly-addictive drug. As a final measure of getting the most out of the resources available, he then served his colleagues the meat not used in the process.
The Empress had specially-contained human brains used to disrupt psionic powers and one of the main characters started the series as an organ runner.
In the Ursula K. Le Guin short story "Paradises Lost", when people die their bodies are taken to the "Life Centre" for "recycling". The story takes place on a generation ship where all resources must continually be recycled for everyone to survive, so it makes perfect sense.
In the Biofab War space opera by Stephen Ames Berry, 'mindslavers' are starships that use the harvested brains of living humans as biological computers. This is reversible (assuming the body is retained), but usually involuntary and is considered a Fate Worse than Death.
Dinotopia has a dinosaur version of this, although it's voluntary. Dying saurians travel into the rainy basin to give their bodies to the carnivores for food. There are similar caravans of mammals that go into the Forbidden Mountains for the same reason.
In Animorphs, there's an alien version. Ax tells the group of a race called The Five that harvested a race called the Venber for lubricants. Their bodies melted when they got above a certain temperature. Eventually it lead to the Venbers' extinction.
There's also the brother of Visser Three, who kills humans to obtain other Yeerks to eat, so he doesn't have to return to the pool to feed.
In The Belgariad, it's mentioned that human skin is seldom used for writing evil books. But only because it's really bad at holding the ink.
In the Breaking the Wall trilogy, the Thirteen Orphans' each possess a Mahjong set that's passed down family lines, with tiles made from bone and bamboo. It is revealed in the second book that the bones came from the original Orphans, exiles from another world who wanted to keep the link to their homeland alive, strengthen the powers of their descendants, and also give their bodies a more portable form in the hopes that they could one day be returned to their homeland proper.
In Courtship Rite, in addition to eating their dead, the Getans make full use of their corpses, since they have no other large animals to provide things like leather. Even Oelita the Gentle Heretic, who preaches against cannibalism, wears a coat made from her dead father's skin, in his honor.
Firebird (Lackey): Anyone who isn't a prince and enters the Katschei's palace is fed to the monster staff.
In Under a Graveyard Sky, the fastest way of collecting large amounts of antibodies for use in a vaccine against H7D3 is to collect the fluids from the head and spine of its victims. The task is done under secret conditions by Thomas Smith and some associates due to the illegality of the act.
In the Vorkosigan Saga novel Ethan of Athos, the bodies of people who die on the space station are processed into fertilizer for plants because the people of the station can't afford to waste organic material and it's considered less Squicky than using them as feedstock for meat replication.
Live Action Television
The clockwork robots in the Doctor Who episode "The Girl in the Fireplace" rebuilt the ship out of parts of the crew.
Also from "The Runaway Bride": "It was all there in the job title, the head of Human Resources."
Adipose: The fat just walks away.
The Dalek Emperor specifically extracted cells he deemed "worthy" from the humans he harvested and grew them into Dalek-Human hybrids.
Professor Lazarus in "The Lazarus Experiment" drains people away leaving emaciated husks.
In "Fight or Flight" the crew find a starship whose murdered crew are being siphoned for their 'triglobulin' — apparently used for medicines, vaccines, and even aphrodisiacs. Unfortunately triglobulin is very similar to human lymphatic fluid…
On an episode of Star Trek: Voyager, the crew met another Starfleet crew in the same predicament they were, but were rapidly on their way back to Earth. Trouble was, they were using sentient beings as fuel. They weren't human, didn't even look humanoid but they screamed horribly when they were in pain.
In the TV movie that kicked off Lexx, the remains of the thousands of offenders executed under His Divine Shadow are chopped up and fed to the ever-hungry titular living spaceship.
The Lexx got the choicest morsels, the rest is donated to the "protein bank" along with all other 'spare' human parts and bodies. As well as a source of parts for cyborgs and presumably also replacement organs for the wealthy, the protein bank was being used to feed the Gigashadow, the last survivor of humanity's deadliest enemy, the Insects. In the final TV movie, the entire population of the League of 20,000 Planets was harvested for their flesh.
In Torchwood: Children of Earth, the 456 want 10% of our children to harvest drugs from them.
A short segment of Night Gallery featured a man whose business was getting passage out of the country for the most reprehensible murderous criminals. He did so by toasting his client's voyage and slipping him a mickey, then shipping him out of the country...as canned dog food.
Subverted in an episode of Tales from the Crypt. A woman kills her husband and shoves him into a processor meant to make soap, then takes the soap home for use. The result proves to be dangerously acidic.
An episode of the new Twilight Zone presents a family moving to a neighborhood where the rebel teenage children are sent to a place which starts seeming some kind of camp or disciplinary place. In the end, however, it's revealed that the kids are turned into organic fertilizer and the parents are given a tree fertilized with their child as a memento.
In Being Human, the vampires eventually try to control their hunger while they work on world domination by keeping a group of humans in the basement for slow drinking. Though the humans are promised that they won't lose much blood, it is gradually revealed that the people are getting sick from blood loss and that there were items left in the room from the first groups of people that were brought in... Thankfully, Anne promptly rescues everyone from the room after she meets the ghost of a man who died in the room.
In Dollhouse, the mysterious and sinister Attic turns out to be a place where those who have really offended the higher-ups are kept in a comatose state while their brains are used as living RAM by the Dollhouse mainframes.
Angel had an episode where humans were harvested for parts for transplant to rich people.
Also there was a necromancer who main source of income was putting demons into corpses provided by Wolfram & Hart.
An episode of the new Outer Limits involves first contact with a bodiless alien race fleeing the destruction of their home world. Since they cannot survive indefinitely in this form, they request that they be given dead humans as hosts.
Subverted in a season six episode of Buffy the Vampire Slayer. Buffy did believe that the Doublemeat Palace ground their employees up into hamburger, a theory supported by the disappearances of employees and after she found a finger in the meat grinder. It turns out that the employees were in fact eaten by a lamprey-like demon disguised as an old lady regular customer.
Subverted on Ink Master, when the host implied the contestants would have to tattoo human corpses as part of a challenge. They wound up working on plastic dummies instead.
One of the Real Life weird artists who shop at Obscura from Oddities specializes in using stuff like human hair, teeth, belly-button lint or nail clippings in her craft projects. Quite a bit of Obscura's stock likewise consists of human bones or other preserved remains.
Technically, Vampire Resources in this case. A 700-year-old vampire chick in Moonlight traps other vampires in a vat of silver (toxic to them) and processes their blood into a drug called Black Crystal, which allows a human to temporarily feel the rush of being a vampire (minus the bloodlust). When Beth takes a hit from BC, she tries to seduce Mick and begs him to turn her. Unfortunately, the high content of silver is toxic to humans too.
Two episodes of Sliders deal with organ replacement. In one, any person under 30 is required to be an organ donor, even if said organ is vital. When someone rich and/or important needs a new heart, the computer randomly selects a healthy 20-something with a good heart and activates his implant. The implant acts as a tracking device for special squads. Another episode has rich or important people being cloned and kept in a vegetative state in order to have perfectly-compatible organs. The problems arise when "our" Quinn is thought to be an escaped clone for this world's Quinn, who had just lost his eyes.
Hannibal, which is based on a series of novels involving a cannibal doctor, takes the concept and runs with it, by having the villains-of-the-week turning humans into anything - furniture, fertilizer, artworks, instrument string...
Child Ballad #10, "Twa Sisters": the body parts of the drowned girl are fashioned into a musical instrument, either a harp or a fiddle. The song is covered by Loreena McKennitt in "Bonny Swan".
The "Hand Of Glory" was the severed hand of an executed criminal, clutching a candle or each finger made into a candle (with the added bonus that the candle is sometimes made with human fat), which gave a light only the Hand's holder could see. Supposedly it was a useful tool for medieval housebreakers, who could rob a house after dark without its illumination alerting residents or neighbors.
In some versions of the tale, it went one step further - anyone who saw the light, other than its wielder, was hit with a full-on Hold Person effect until the light left their vision.
Dungeons & Dragons: flesh golems. It's worse in Ravenloft (creators usually are driven by obsessive insanity, while golems, no matter how innocent they start out, sooner or later become Axe Crazy), but otherwise it's merely a very unappetizing variant which is still considered better than Undead. Ravenloft's Hands of Glory and the Eye of Vecna are also examples.
Similar to the Biofab War example, certain ships in the Spelljammer setting use a sadistic variation of the typical spelljamming helm called a lifejammer. Instead of a spellcaster fueling the ship with his or her magical power, lifejammers are powered by the life force of whichever poor victim gets strapped into the helm. Neogi slavers are fond of using them, as are the undead, and their use is banned in pretty much every civilized region of wildspace.
In Paranoia Alpha Complex's main food source is from algae tanks which are in part fed by recycled citizens.
A running joke in Warhammer 40,000 is that the only resource the Imperium of Man is not short on is people.
Space Marine Apothecaries do this literally: their main task in battle is to harvest the geneseed (DNA) of their fallen comrades.
To the point where an infamously ruthless general forced his armies across minefields to clear then for his tanks.
Commander Chenkov once ordered for a wall to be built to protect against his enemies. When the men informed him there wasn't enough mortar and bricks, he ordered them to start shooting his own men, and made a wall out of their corpses.
Servitors, which the Imperium uses in place of robots for heavy lifting and menial labor, are created by lobotomizing a human and grafting them into the machine they are to control. Robots and true AI have been banned by the Imperium due to religious reasons caused by an AI/Human War in the remote past. This war is also implied to be one of the foremost reason of the Dark Age of Technology end.
Also, juvenat treatments (chemicals that stave off aging and increase life expectancy by hundreds if not thousands of years) are implied to be made out of children.
The Medusa V campaign ended with the Dark Eldar capturing enough human slaves to use them as starship fuel.
On top of all this, the Imperium uses psykers to power the Astronomican that guides its ships through the Warp and the Golden Throne that keeps the Emperor alive. An average of ten thousand burn out and die every day. The Throne has been described as having pyskers physically fed into it - at least the Astronomican "only" burns out minds.
The Tyranid top them by attacking with their Cannon Fodder troops to cause the enemy to waste ammunition before the real attack starts, since they'll just lap up those troops' biomass (biomass being anything organic) to make more later, then eat up the enemy's. Said troops don't even have a digestive system! They're supposed to get wiped out.
In MacBeth, the potion that creates the apparitions requires some human bits.
In Front Mission for Super Famicom the main villain uses the heroes girlfriend's brain as a computer for his mech. You can eventually install "her" into your own wanzer.
In Red Alert 2, you can gain funds by sending infantry back into the Cloning Vats. In the add-on game Yuri's Revenge, the antagonist faction has a building specifically for this purpose, called a Grinder.
The Grinder returns as a Soviet structure in Red Alert 3, where it's called the Crusher Crane. If you're feeling more charitable, it can also repair vehicles.
Red Alert 2's editable INI files refer to the recycle-value of a unit as "soylent", in a fun bit of referential humor.
Yuri's power plants could also improve their output if a soldier (One of Yuri's army or a mind-controlled enemy) was forced inside. However, this is a temporary boost, as the soldiers can leave the power plants again.
CABAL in Command & Conquer: Tiberian Sun is an artificial intelligence that stores human in vats so it can use their brains' processing power. Its name is an acronym for "Computer Assisted Biologically Augmented Lifeform".
In Warcraft III: Reign of Chaos, the undead can store corpses to be eaten or resurrected for later use. Of course, they are undead. Their siege weapon is the Meat Wagon which throws bodies as ammunition. Luckily, these corpses spawn from thin air and you don't have to collect any for that purpose.
In addition, the undead in World of Warcraft have the racial ability "Cannibalize" which allows them to regain health by eating a corpse.
A few undead units in Warcraft III have this ability too.
The Death Knight class introduced in the second expansion has the ability to raise a humanoid corpse as a temporary pet for a few minutes or as a lifelong companion if enough points are put into the proper talent tree.
Including allies. Word of caution: some people really don't like it.
Update: Death Knights have apparently gotten better at it, because their "Raise Ally" button is now a full battle resurrection.
The recycling tanks in Sid Meier’s Alpha Centauri. The supplementary materials implies that it's mostly the carbon and water that's being recycled, the two being rarities in the heavily nitrated soil and atmosphere of Planet.
"It is every citizen's final duty to go into the Tanks, and become one with all of the people." — Chairman Sheng-Ji Yang, 'Essays on Mind and Matter'
Star Control II does this with the Druuge, whose Mauler ship has a ridiculously low recharge rate for its weapon. Luckily, the Druuge keep all their crewmates conveniently close to the engine intake.
The game tends to objectify life in general: your ship's life units are its crew members, and if they die, it's no problem for you as long as you have enough Resource Units to buy more. Moreover, you collect Resource Units after winning a battle by scavenging minerals from the enemy ship's wreckage. It seems as though a planet's inhabitants are sacred, but once those inhabitants are aboard a ship, they are expendable, at least to an extent because if you use lose a lot of crew members, the price for new crew members goes up. Same happens if you sell too many of them to the Druuge as slaves. There is a optional sidequest where you can save the Shofixti race, who have ridiculously fast reproduction rate, thus creating an effectively endless pool of volunteer, bushido-following, loyal and eager to sacrifice themselves for you recruits, resulting your crew cost to be reduced to lowest possible.
The Combine of Half-Life 2 have a lot of this, most notably the stalkers.
Harvesting humans to turn into goofy robots was the primary purpose of the giant sphinctership in Prey.
The Adam economy of Rapture, from BioShock, is built on this. First, the Adam (a valuable genetic commodity/drug) is made in the bodies of modified little girls grafted to an outright miraculous sea slug. These self-same little girls are set loose to gather Adam from the bodies of dead splicers. Not to mention that the monstrous Big Daddies that protect them are extremely bio-modded humans in armored diving suits. It's implied within the game that the Big Daddies are created out of out-of-work and down-on-their-luck people. There are signs about an orphanage and a halfway house right near where the Little Sisters and Big Daddies are created.
In the video game Xenogears it is eventually revealed that the human race (of the game's world) was created by a cyborg computer to be eventually used as spare parts!
At one point Fei, Citan, and Elly discover that when in Solaris, one should not eat the food. Ironically they discover this in the food plant itself. Fei and Elly break open a few barrels at the end of the production line to appease their growling guts. They even comment on how good it tastes. Citan refrains, but lets them eat anyway. The characters then walk into the next part of the plant, and well... you can imagine what happens next.
Fallout starts with 'Iguana' Bob, whose stores tend to include a slight bit of long pig when the iguana is low. Fallout 3 also includes the people of Arefu potentially giving blood to the Family in exchange for protection or being left alone, and the children of Little Lamplight, who are only able to survive thanks to the radiation-cleansing properties of a specific fungus that suddenly flourished after having all the dead adults dropped into it. The Little Lamplighters continue to provide nourishment for said fungus. The player character in Fallout 3 can also sell human blood and... ahem... strange meat to some of the above groups, although not usually producing it himself or herself.
Not to mention the Cannibal perk, which lets you eat corpses and people you kill. Rather nutritious, too. Just don't let others know of your disgusting habits.
In Quake II and Quake IV, the Strogg use the bodies of humans to increase their ranks, to break down into Stroyent, and to power their machinery, amongst other things. Your first encounter with this rather nasty aspect of the Strogg is the second objective of the fifth mission of Quake II, which has you shutting down an alien processing plant. In Enemy Territory Quake Wars Strogg technicians can convert fallen GDF sodiers into single use respawn points for Strogg players.
It is also implied that the Strogg that are not made from humans are made from other alien races the Strogg have conquered.
Dwarf Fortress allows you to make crossbow bolts from the bones of your enemies. Creative modding also allows you to butcher captured and / or fallen enemies for food and other by-products.
Each dwarf has a chance to go into a "strange mood", which will result in them producing a legendary artifact. If the dwarf is miserable at the time the strange mood stirkes, there's a chance he'll murder a fellow dwarf and make some leather craft out of the dead dwarf's skin.
Mermaid bones were once a very valuable commodity, as merfolk are incredibly rare. Someone figured out a way to make a mermaid farms by carefully managing a "captive" population so that they would breed fast enough to have a reliable supply. Toady was horrified by this and lowered the value of mermaid bones drastically in a later update.
In System Shock 2, the Many, early on, connect worms to humans to change them into Hybrids. Later, having gained control of the Von Braun, they start converting people into their raw components and building new creatures out of the biomass.
Near the end of Magical Starsign, you learn the robots are powered by gummies made from humans. The humans forming the gummies are all that's left of the Espresso civilization, and when they run out, every robot will turn against every civilization in order to make more. Mood Whiplash indeed!
Humans are this to the Reapers in Mass Effect, but it's not clear exactly how, since the Reapers go on about how you couldn't possibly understand. The game hints that the husks might have something to do with though. Likewise the Collectors in Mass Effect: Ascension, who may or may not be the same group as the Reapers (they're never seen and nobody knows anything concrete about them).
In Mass Effect 2, it turns out that Reapers are constructed from a combination of mechanical components and the liquefied and processed bodies of organics, making them strange cybernetic organisms.
Mordin's loyalty mission has him and Shepard discussing the use of live test subjects (human and otherwise) in medical research. Mordin states that humans make excellent test subjects for such projects due to their greater genetic diversity compared to most other species. However, he disapproves of such methods on moral grounds, saying that they have no place in real science.
In Mass Effect 3, you visit a massive refugee camp on Horizon, that is run by a a group that is entirely controlled by Cerberus. Not only is the place completely deserted, files found on desks of the administration staff refer to the reception terminal as "Processing". All healthy adults are turned into mind controlled cyborg soldiers while everyone else is made into husks as samples for Anti-Reaper weapon tests.cr
The Big Bad of the Citadel DLC is revealed to be a clone of Shepard, created by Cerberus as part of the Lazarus Project to provide replacement organs and limbs in case Shepard was critically injured during the Collector Mission. S/he has none of Shepard's memories and was never even supposed to be conscious and naturally, developed something of an Inferiority Superiority Complex towards the real Shepard as a result.
In Unreal, the Mercenaries in the Terraniux hydroponics facility are either fleecing the Nali for fertiliser, or using them as fertiliser:
Translator Message: Greenhouse B: The Karkilys Zegnus need more fertiliser. Please dispatch a group of guards to inspect the Nali homes in Noork's Elbow.
The Flood from the Halo series starts out as a typical example of The Virus, infecting living beings and transforming them into Combat Forms. However, once it took over the population of the Covenant holy city the Gravemind started producing Pure Forms - creatures built from scratch out of collected biomass.
In the Season 3 episode The Penal Zone, the arch-villain harvests moleman sweat (not exactly human, but still...) as condiments and rocket fuel. A escaped victim would later run in the streets, screaming a la the final scene of Soylent Green.
The player character in inFAMOUS can pull energy from other people to fuel his powers. The game's MacGuffin does this on a much larger scale.
In Oiligarchy, you can eventually start processing people into biofuels once oil starts running out.
In the Codename: Kids Next Door game Operation: V.I.D.E.O.G.A.M.E, Father uses the bodies of all villains the team defeated to create the last boss, The Amalgamation.
Killing enemies with Damage Traps in Tecmo's Deception only makes them drop gold. However, if you successfully finish them with a Capture Trap, you have the choice of taking the gold off their corpse, sucking their soul out to restore your Mana Meter, or entombing their actual bodies to be used to create a monster for Summon Magic.
Prototype is quite literally made of this. The plot revolves around a virus that warps and re-purposes human bodies for its own ends; the creatures Alex fights are grown from infected humans (which in concept art is depicted as packed-together human bodies, still somewhat alive, being gradually assimilated into the larval form of the creature); one boss fight is against a woman literally encased in human flesh, which she uses like a gigantic set of Power Armor; and Alex himself absorbs people to take their memories, appearances and mass to fuel his abilities, 'consuming' them alive.
In Final Fantasy Type-0, "Phantoma" can be absorbed from dead organic enemies (Including human soldiers). Absorbing Phantoma replenishes the character's MP, and collected Phantoma is used in the Altocrystarium to power up spells in multiple parameters (Strength, range, MP consumption, etc.)
The demons in Corruption Of Champions strap people into chairs, inject drugs, corruptive fluids, and aphrodisiacs into them, and then milk them of their sexual fluids for the rest of their lives. This is a potential fate of the player character.
In OddworldAbe's Oddysee, the titular Abe and his fellow race, the human-like Mudokons, are the slaves of Rapture Farms, the biggest meat-processing plant on the planet. And because Rapture Farms has processed so much livestock into extinction, the Glukkons, an entire race of Corrupt Corporate Executives, decide that their newest product will be the Mudokons themselves! The second game, Abe's Exoddus, has the Glukkons making drinks from Mudokon bones and tears.
Minecraft has a subtle example: Zombies and Skeletons both drop useful items. Skeletons in particular drop bones, which are useful as fertilizer, while Zombies drop Rotten Flesh, which is less than ideal for proper meals but is useful in a pinch. Both of these are implied to have once been human, especially the Zombies, which have an appearance that's almost identical to the default character skin. Additionally, Rotten Flesh gives the player a temporary Hunger effect when eaten.
Ultima III Had an interesting case of Video Game Cruelty Potential: You can drum up some quick, easy cash by creating new characters for the party with the express intent of selling all of their equipment. But that's not all! There's a place in a town where you can donate blood (reduction of hit points) and you get payment for it! So before you delete those naked characters you can sell almost all of their blood for cash!
Shin Megami Tensei: There are several substances you can find across these games. Demons love 'em all, magnetite, magatsuhi, red pills, what's the diff? All taste great and give lots of energy. The method of production, though? It involves humans, torture and very, very painful extraction. There's a reason it's been called true evil.
Cave Johnson: Just wanna let the cafeteria staff know to lay off the Soylent Green. I'm holding a memo from the President, and it turns out that soylent green is... [paper rustling] let's see here... doubling in price."
In The Forest, both the player can use the cannibals bodyparts as effigies to scare them off, while the cannibals have used human limbs to create some themselves. Also, the cannibals got their moniker for a reason.
In Wild Star, playing with and utilizing the dead for your own purposes seems to be a real recurring theme.
First up, there are the Moodies who raise the dead as servants, and themselves when they meet an unfortunate end.
Next up, there are the Mordesh, who need Vitalus so badly it is actually protocol to extract the chemical from dead Mordesh.
Speaking of which, both the Mordesh and the Chua are not adverse to test subjects that are little less than fresh for their experiments. While they would certainly prefer live ones, one simply does not have the luxury most of the time.
Heroic Spirits, due to their inability to regenerate their own prana, usually rely on their Masters to restore their reserves. In desperate circumstances, or if the Master simply wants to quickly power up their Servant, the Spirit can resort to consuming souls. Due to their Masters lacking prana, Caster and Rider did so.
The Holy Grail converts the souls of Heroic Spirits into energy to power itself. Caster determined it could also be powere by ordinary human souls, though in much vaster quantities.
Hatoful Boyfriend's all-birds high school has a rumor that the students who vanish in the infirmary are used for diabolical experiments and then converted into teriyaki for the lunch menu and quill pens for the bookstore. There's significant evidence that these rumors are true, but the government does nothing... because they're sponsoring the Mad Scientist who is the school doctor!
In Drowtales humans are constantly kept as slaves, cheap labour and meat shields by the Drow races. Well not being outright kept for eating, partly because it takes too long for humans to mature enough to be worth it, when a human dies the drow have no qualms butchering and serving them as food, but they also frequently do this to other drow, as food is too scarce in the underworld to waste. The Black Dragon Tavern is also shown to have fed humans and other drow who became useless in their Gladiator Games to their growing dragon hatchlings.
Implied in thisS.S.D.D where the head of the CORE wonders how the Collective of Anarchist States could get the carbon and calcium to build the Tower of Babel from the wreckage of post-hurricane New York.
Federov: "...I've just thought of a way to supplement a carbon and calcium supply after a natural disaster. Please say I'm wrong."
Central: "There's been a distinct lack of televised funerals from the CAS, so sorry sir, I can't rule it out."
The present page image is from Schlock Mercenary, in a storyline where kidnapped humans are used to develop illegal nanites.
In Unsounded "Plods" are corpses that were deliberately reanimated with pymary (magic), and are widely used as a cheap source of slave labor. They are considered quite ordinary in the countries that "employ" them; making a mindless magical meat-puppet do punishing work for days at a time is said to be a more humane practice than enslaving living, feeling humans. Their use is heavily regulated, as is their appearance, which is made uniform and featureless to prevent an Uncanny Valley effect, and areas where they are working are often cordoned off so as not to disturb the living.
In Lucky Day Forever, the Lottery Winner bodies are used to revitalize the Whites's bodies while keeping the Whites young forever. This trope metaphorically represents the Whites taking advantage of the gullible Proles.
In The Return as well as the Other White Meat, Succubae feed on human sexual energy. One of the markers of the "good guys" is that when they do it, their victims are still alive afterwards. Alexia's victims are not so lucky.
In The Sandstorm episodes of Welcome to Night Vale, everything in Desert Bluffs is said to be made out of or covered in viscera. Possibly implied to be the fate of one of the Intern Danas - they ran out of materials, and the surviving Dana had to build that shelf out of something.
Homer: Marge, please, old people don't need companionship. They need to be isolated and studied so it can be determined what nutrients they have that might be extracted for our personal use.
Marge: Homer, would you please stop reading that Ross Perot pamphlet?
A nonlethal example in Ugly Americans, where the Gay Pride Parade powers the New York electric grid.
A rather painful and Squick-y example from Aqua Teen Hunger Force: The trees, upset at the way people have been treating them, puts Master Shake on trial; during the trial, they bring out Carl... and rip pieces of his skin right off his body to use as paper.
A season 2 episode of Metalocalypse reveals that the favorite sewing material of band's new fashion designer is "special leather". The final scene, which shows the room where he harvests this material, is so Squicky that even the band is horrified.
Mary Roach's Stiff examines the various fates awaiting actual human remains, including dissection, vehicular crash-testing, being plastinated as a permanent anatomical display, or getting processed into cement for an artificial reef and/or fertilizer to sustain a memorial tree.
The organ donor system; you agree to it, then fall over dead, and some doctors cut all the useful bits out of you to use in someone else. Often it is illegal for the donor's family to profit by this; in some countries there is a small payment.
Likewise, blood banks and marrow-donor registries, with the added convenience of omitting the "fall over dead" part.
Sperm donors also fall under this.
During WWII, when the Nazis gathered up Jews to take them to concentration camps, they first stripped them of all valuables and possessions and sold them. Then they pulled out any gold tooth fillings that they might have had, melted them down into gold bars, and sold those as well. Then they used the healthy ones for slave labour in the camps until they were worked to death. Some camps processed the dead bodies into products, making cloth from their hair and fertilizer from their bones. The Holocaust museum at Auschwitz has some of the cloth.
Hair from concentration camp victims was woven into thermal socks and underwear issued to U-Boat crewmen and Luftwaffe aircrew. It was also used to fill mattresses issued to prisoners of war; one British Po W recalls marveling that the Germans were methodical enough to collect all the gleanings from barber and hairdressers' shops for re-use...
And then there was one Dr. Joseph Mengele, who was quite happy to use the prisoners of Auschwitz in his horrible medical experiments.
Partly due to the massively racist anti-Japanese propaganda by the Americans, the taking of "souvenirs" from the corpses of Japanese soldiers was common during the Pacific campaign. (By contrast in the European theater the only verified case of this was of a single German corpse scalped by a Native American soldier.) This practice contributed significantly to Japanese reluctance to surrender.
There's currently a war crimes tribunal about American soldiers who may have done this "souvenir collection" with Afghan civilians.
Played for Laughs by McDonald's restaurants. Today, the tray liners display nutritional information. In the late 1980's, they had a picture of happy-looking employees with the caption, "People, our most important ingredient."
A 14-year old British girl named Charlene Downes was alleged to have been raped and murdered by 29 year old Iyad Albattikhi, owner of Funny Boyz fast food shop in Blackpool, UK. To hide his crime, Iyad was alleged to having ground her body into kebab and sold her as kebab meat to customers in his restaurant. Basically, if true, this would be a Real Life version of Sweeney Todd.
There was a report that Chinese "vitality pills" contained powder made from ground-up babies.
If you boil human urine, you can condense the vapor back into liquid. The liquid is just water. This is also how NASA keeps the astronauts hydrated in the ISS as water is expensive and heavy to ship up to orbit.
Extracting the phosphorus from urine is now seriously considered since mineral stocks are limited. Also as the sheer amount of phosphorus from humans is causing algae blooms in water sheds.