The Virus



""Jesse is dead! You have to remember that when you see him, you're not looking at your friend. You're looking at the thing that killed him.""

- Giles, Buffy the Vampire Slayer

The Virus comes in many forms in many genres. Simply put, The Virus turns people into itself or into entities subservient to itself. The transformation is both mental and physical. The converted will have unflagging loyalty and be instantly ready to commence villainous actions. Expect it trying to cause The Plague.

If the converted still resemble their previous selves, they will use their personal knowledge to prevent their former loved ones from doing them harm, or from trying to get them back. Despite the body snatching, if The Virus is only able to crudely mimic human behavior it may lead to a Glamour Failure that's especially noticeable. Some strains of The Virus are so powerful the infected can even mutate environments. This tends to lead to the Womb Level and Organic Technology.

How much of the former person is left after infection depends on the series, as does whether or not the process is reversible. It also depends on whether it's a main character or not, they can sometimes use The Virus' powers against it with enough Heroic Willpower (a property more typical of The Corruption) and even play Sheep in Wolf's Clothing for a while. If it's one of the main villains using villainous willpower, then they tend to end up on the high end of the Elite Zombie chain. If The Virus is sentient, then more often than not it is also a Hive Mind with a Hive Queen directing it.

Stories of yesteryear often tied this symbolically with the Red Scare; nowadays if it represents something, it's The Heartless. The lowest common denominator for man to sink to, susceptible when one lets their own Dark Side take over -- and it takes people around them down too.

Often how humans become something much, much more horrible.

Sometimes overlaps with Body Horror in cases where the host enters a zombie-like state before being completely consumed. Compare Viral Transformation, where a similar change does not cause a Face Heel Turn. See also Puppeteer Parasite, Face Full of Alien Wingwong, Contagious AI, Fisher Kingdom, Monster Progenitor, The Corruption, The Assimilator and Zombie Apocalypse. Commonly represented with Tainted Veins or a Red Right Hand.

Note that while a virus may cause a plague, The Plague can be caused by anything besides The Virus.

Anime & Manga

 * Galaxy Express 999's Machine Empire is an intriguing subversion, for while they are rather obviously cut from the same cloth as the Cybermen and the Borg, and wage brutal wars of conquest, they don't generally convert conquered races by force. In a late episode featuring a planet whose government, a minor satrap of the Empire, had recently begun forcibly converting humans, a leader of the Empire actually rebukes a local official for the damage this policy was doing to their cause.
 * The Invaders from the Anime Gate Keepers and its dark sequel, Gatekeepers 21.
 * Venus Versus Virus: The Virus changes humans into demons.
 * The Festum in Fafner In The Azure Dead Agressor.
 * In one chapter of The Kurosagi Corpse Delivery Service, a real-life parasite that infects snails begins to infect humans instead, with art that puts the horror back in Body Horror.
 * This happens to entire planets in the Salamander OVA.
 * Higurashi no Naku Koro Ni takes this in a somewhat weirdly literal direction with
 * The Dark Spore in Digimon Adventure 02, though its effects tend to be somewhat More Than Mind Control.
 * Blue Drop has a somewhat lesser example. The second manga, Tenshi no Bokura, implies that any human female sexually exposed to the One-Gender Race Arume (a species of alien lesbians who reproduce by a complex-and-imperfect genetically engineered Homosexual Reproduction process) becomes somehow psychologically incapable of loving a man, possibly due to special pheremones (a form of chemical warfare?). The implications for both species, as well as the results for society, are truly horrific.
 * DG Cells from G Gundam, proving that the only thing worse than zombies are cyborg zombies. With giant robots.
 * The anime of the series Le Chevalier Deon has this trope. In that people being controlled by the Psalms turn into "ghouls" who bleed silvery blood and their flesh is all gross looking. They don't seem to have control over their bodies, though in typical fashion the "infected" may have some dying words such as "kill me" to mutter.
 * The series Red Garden has this as well. In the first episodes those affected by "the virus" appear to be superhuman. One of them also walks like a dog.
 * Consequently, it ends up being
 * The Spiral in Uzumaki.
 * Yu-Gi-Oh GX: The Light of Destruction. More typical of The Corruption when it comes to Yubel. Certainly this trope for others it affects.
 * The Kanshuu from World Embryo. Traveling through cell phone signals, any person who listens to their phones and hears these signals mutates and contorts into another Kanshu. It gets worse since anyone who knew those victims in life, be it parents, friends, siblings, etc., will have their existence completely wiped from their memories, causing them horrible mental trauma.

Comics

 * The OMAC from The DCU are complex nanomachines that hide in a person's body until they are kickstarted through a command by Brother I. They proceed to take over the inhabitant's body and turn him into one of the electric blue, one-eyed killing machines. Ironically, they were spread through tainted flu shots.
 * It's an awfully sexist virus, too, as it will seemingly convert even a female human into a male OMAC!
 * For a Marvel Universe equivalent, during the "Operation Zero Tolerance" arc, Bastion turned certain people into "Omega Sentinels" by abducting them, filling them with nano- and cybernetics, and placing a sleeper program in them that would activate in the presence of mutants.
 * The comic book series Powers had an arc that revolved around a dangerous and addictive superpower, (can anyone say drug addiction allegory?) that was spread between people, infecting new users.
 * The "Legion of the Damned" arc in DC's post-Zero Hour Legion of Super-Heroes features the Blight, which ravages the United Planets and takes over most of the Legion before the remaining Legionnaires manage to purge it.
 * In DCU's Final Crisis, Big Bad Darkseid uses the Anti-Life Equation this way, bringing Earth under his control, and transforming some of the heroes into his monsterous servents.
 * Ironically, Checkmate uses the millions of people infected with OMAC nanotechnology left over from the last crisis in order to fight against the Anti-Life Justifiers, making this a Virus versus Virus situation.
 * This was the power of Weapon XII, a villain appearing in New X-Men 129-130. Every person or animal he touches develops glowing eyes and permanently becomes an extension of his mind. By the time Xavier and Jean Grey arrive to deal with him, he's infected most of the humans in the Chunnel, several hundred of Multiple Man's bodies, and a collection of birds, bats, and dogs.

Fan Fiction

 * In Divine Blood, Kodachi Kuno is this via Agent Smith style Mind Rape targeted at anybody with mental powers or borrowing mental powers via a spell. She mostly targets her own mass-produced biological daughters early on.
 * In Project Tatterdemalion, a Sci Fi/horror AU of Bleach, Hollows are the result of an alien Synthetic Plague called "Madsen's Hollow". It transforms one-fifth of the infectees- those with all of a set of genes that make them vulnerable to it- into monsters with Combat Tentacles and a drive to infect others to reduce their loneliness. The other eighty percent die messily from the incomplete effect. Interestingly, there is a vaccine- although it does have some side effects.
 * By the same author, in Upon A Fiery Steed, this is what Shin no Yami used to be.

Films

 * Invasion of the Body Snatchers is all about this.
 * Many classic vampire and Werewolf movies had those bitten (or killed) by the monster becoming monsters themselves.
 * The 2009 film Daybreakers plays with this in interesting ways. Humans bitten by vampires will turn into vampires, resulting in almost the entire population being turned by the time the film is set.
 * Same goes for a lot of Zombie Apocalypse movies as well: "The people it kills get up and kill!"
 * Except that Romero zombies, at least, get up and kill simply because they are dead, not because they have been specifically infected.
 * The Thing (from the 1982 John Carpenter movie, the 1951 film The Thing From Another World which inspired the John Carpenter movie, and, lest we forget, the story Who Goes There? which inspired both movies) is the literal embodiment of The Virus -- a fiendish micro-organism that replaces the victim's cellular structure with itself. The Thing also displays the ability to perfectly mimic any living thing -- until it's threatened, at which point it flips out and begins sprouting tentacles, giant toothy mouths, etc.
 * Agent Smith in The Matrix sequels. After Neo tried to delete him, he comes back and now can copy himself into other people. Ironic, given that he was disgusted by the human race and called them a virus in the first movie.
 * Also, for symbolism points, his sunglasses changed after his resurrection. Originally they were square, and now they're slightly more rounded, and have the general shape of a protein capsule of most viruses.
 * Throughout the Matrix Trilogy all the Zionites and their supporters (Seraph, The Oracle) have round glasses while Agents and their sympathizers (Cypher) wear square ones. The fact that Smith's glasses are something in between furthers the symbolism and is another example of the series' Fridge Brilliance.
 * The 2008 horror movie Quarantine (and the movie it was a remake of, REC) picked up on the appropriateness of rabies as an example of The Virus by making a mutated version the film's threat.
 * In the original REC it was suggested that The Virus has a more... supernatural origin.
 * As the name implies, the antagonist from creepy 1999 film Virus. A transmission from space takes control of a (seagoing) ship's computers and begins building something. When the heroes ask the program what it wants, it replies with a list of body parts.
 * The alien in Slither, which spreads through parasites that turn hosts into drones for the Hive Queen, controlled through a Hive Mind.

Folklore

 * Vampires. In almost all versions of those myths.
 * Werewolves in more modern versions.
 * Zombies in some more modern versions.
 * That most dreaded and contagious of schoolyard infections: Cooties!

Literature

 * The hermaphroditic eponymous race in Storm Constantine's Wraeththu books change young human men into Wraeththu by transfusing them with Wraeththu blood, then stabilize the transformation via sex.
 * The Yeerks from K. A. Applegate's book series Animorphs. They are a race of parasitic slugs who infest a host body by entering through the ear and wrapping themselves around its brain. It can then read the hosts mind and control the host's every action, imitating its behaviorisms. The mind is left a prisoner, able to think freely but unable to control any aspect of their physical selves. They are returned to themselves briefly every three days, when the Yeerk needs to feed.
 * A unique example from Charles Stross' SF novel Singularity Sky: Mimes. Mimes who reproduce themselves by hitting humans in the face with pies -- the pies are full of nanotech that reformats the human into a new Mime, complete with more pies. Lucky for those being pursued by Mimes, they are afflicted with the sort of tics you'd expect, such as occasionally being trapped inside an invisible box or having to walk against the wind.
 * Stross also created "Curious Yellow" in the novel Glasshouse. CY was a digital virus that was capable of controlling people and removed their memories (as well as computer records) of... something. What no one ever found out, even after the long, brutal war to contain and defeat The Virus.
 * A particularly unusual example shows up in Philip K. Dick's novel The Three Stigmata of Palmer Eldritch. The title character distributes an exceptionally trippy drug with the side effect of causing the users to think more like he does than they used to -- and also causes them to spontaneously develop Palmer's "three stigmata", which are artificial eyes, a metal jaw, and a replacement arm.
 * One of the creepiest examples ever is Philip K. Dick's short story Upon the Dull Earth. A weird necrophiliac woman attempts a bizarre experiment to speak to the "angels" who supernaturally rule the Earth, which fails and claims her life. Her grieving boyfriend bargains with the angels to bring her back in a Deal With the Devil. Unfortunately the angels screw up when doing so -- the girl comes back, but only by hijacking another person's body, taking over her sister's body and physically transforming it into her own. The angels seem unable to stop this process, either -- soon everyone in the world begins spontaneously transforming into a duplicate of the girl. Madness and horror ensues.
 * Another squicky example occurs in Spiral, the first sequel to Ring. Any time a woman watches the cursed videotape (or any of it's derivatives), whilst ovulating, they become pregnant with a clone of Sadako, which develops to birth in a week, leaving the host to die.
 * The Solanum virus from the Max Brooks book World War Z. Lethally toxic to all animal life if ingested. Kills and reanimates humans bitten or scratched by the infected or exposed to their bodily fluids, and can potentiality reanimate infected people who die from other causes while the virus is incubating. Does NOT raise long-dead people from their graves.
 * The Conjoiners, a Hive Mind culture in Alastair Reynolds's works, are actually the good guys in a number of stories. They started out as a handful of scientists who linked their minds as an experiment and subsequently released a virus to assimilate more minds into the collective, but later their goal became simply to survive. They consider conscripting their enemies a more humane alternative to killing them.
 * In Steven Hall's The Raw Shark Texts, Victorian "gentleman scientist" Mycroft Ward gradually becomes this. He cheats death by transferring his personality into a younger man, and this new body cheats it again by sharing knowledge with a second person. It all goes bad when the increased self-preservation instinct causes him to search out more and more hosts.
 * Faction Paradox in the Doctor Who novels had "Faction biodata", which they could inject into such things as regenerating Time Lords or pure life energy creatures melding with a planet's ecosystem, turning their hapless victim into a tool of the Faction via an extremely vicious form of Cosmic Retcon. This would normally be bad. It becomes horrifically bad when the infected Time Lord in Interference is
 * Vord in Jim Butcher's Codex Alera are a sort of gumbo version of this, combining several Virus tropes into one vicious nasty.
 * Dances of the Men by V.Pokrovsky has a new one, in case old bites and microbes were too easy to block. One guy invented a Super Serum-level brain stimulation by complex microwave pulses. When he tried this trick on H.Sapiens, human brain turned out to be different--it re-emitted this. With the power growing until it can melt holes in wire veils at point-blank range, just before boiling itself. Not that it mattered to that veil's owner much--the powers it still gave are deadlier anyway, and most of infectees at the final stage are violently insane. Victims just infected through the wall at the other end of the street emit less than noise level until they get worse, so Im[pulse]Patho[logy] kept to re-emerge.
 * In The Wheel of Time, 13 channelers weaving a particular kind of Black Magic through 13 Myrddraal can forcibly turn any other channeler to the Dark Side. The victims are described as having unnatural facial expressions, "like the smile on the lips of a corpse", and "something not-quite-alive inside those eyes. This didn't seem to be a man, but a parody of one. A shadow stuffed inside human skin."
 * In the Star Wars novels Death Troopers and Red Harvest a virus is delivered through a chemical compound derived from a plant and other Sith formulas, which turns the victim into Zombies. Not kidding, ZOMBIES in Star Wars. The virus is transmitted through bites or exposure to infected blood, and the horde even some kind of hive mind to boot.
 * In Harry Potter, lycanthropy is basically a giant metaphor for AIDS.
 * In Neil Lee Thompsett's Becoming Human, humanity itself is this. Not a species, a disease.

Live-Action TV
"Willow: It's horrible! That's me as a vampire? I'm so evil and... skanky. And I think I'm kinda gay.
 * The vampires from Buffy the Vampire Slayer. Buffy vampires have their previous selves' souls replaced with a demon (though it can be retreived later by a spell). However, despite not really being the same entity, the vampires retain their memories and usually end up being a twist on the original person's personality, particularly the repressed parts:

Buffy: Willow, just remember, a vampire's personality has nothing to do with the person it was.

Angel: Well, actually... (sees Buffy's expression) ... That's a good point."


 * In the episode "Bad Eggs", students participating in a health project raise eggs as if they were children. The eggs end up hatching and the demons inside of them take control of whoever was supposed to take care of them. All of the egg-demons are controlled by the "mother" demon below the school.
 * This is actually a reversion to the original vampire legends in Eastern Europe, in which spirits called upir, which are supposed to be simple psychopomps (escorters of the dead to the afterlife), glom into the now-soulless bodies and walk about in search of fun.
 * And then there's Jasmine from Season 4 of Angel, who turns everyone into her fanatical worshipers willing to kill others for trying to free them from her influence.
 * Ironically though, being infected with her blood frees you from her control. Jasmine refers to it as "spreading the hate".
 * The Borg from Star Trek.
 * The Yeerks from Animorphs. They are a race of parasitic slugs who infest a host body by entering through the ear and wrapping themselves around its brain. It can then read the hosts mind and control the host's every action, imitating its behaviorisms. The mind is left a prisoner, able to think freely but unable to control any aspect of their physical selves. They are returned to themselves briefly every three days, when the Yeerk needs to feed.
 * The Cybermen of Doctor Who, who were arguably the inspiration for the Borg.
 * The "Empty Child" in the new Doctor Who series (from the episodes "The Empty Child" and "The Doctor Dances") was
 * And the Primords in Inferno. If they even touch you -- hell, if you touch that green stuff for even a fraction of a second -- it's only a matter of time before you become a mindless Primord.
 * from "The Waters of Mars",.
 * An unusual one, as it can exist and be dangerous outside of a host as well. It's harder to avoid and does its work faster than most of the examples on this page.
 * The Nucleus from "The Invisible Enemy".
 * The Bane fizzy drink from The Sarah Jane Adventures spin-off of Doctor Who.
 * The demonic virus from the Supernatural episode "Croatoan". No explanation (as of yet) why it didn't affect Sam but affected everyone else who was exposed to it.
 * The revelation at the end of season two that more than likely covers it.
 * Inverted in Stargate Atlantis, where the "good guys" invent a virus that turns enemy Wraith into docile, submissive humans. Of course, they really don't go about this in the best way, and things quickly go downhill.
 * Then there's the Hoffan retrovirus, which makes the host lethal to Wraith attempting to feed on him/her. Problem is, half of the hosts are killed off by the virus itself after a few hours.
 * The Orphenochs from Kamen Rider Faiz.
 * A key trait of Dezumzorya, the Big Bad of Bakuryu Sentai Abaranger. It combines physical infection with More Than Mind Control to great effect.
 * The fungus from Primeval takes root in human skin, eventually taking over the brain and transforming the host into a bizarre killer fungus creature.
 * Random Virus in Ace Lightning: former Lightning Knight turned mentally unstable cyborg. Interetsing in that his old self is still there -- it's just that he can't help switching between them on a regular basis.
 * "The Sickness" from Lost is almost certainly this. For five seasons it was suggested that the Sickness was just the delusion of a madwoman... until season 6, when become infected, start following the orders of the Big Bad and kill a whole bunch of people.
 * On Lexx, the Big Bad of Season 2 is Mantrid, a Mad Scientist in a robotic body who creates an army of flying robotic arms that convert other living beings into more flying robotic arms.
 * Not just every living thing. Every thing. Including the stars.
 * Epideme from Red Dwarf is an intelligent artificial virus designed to block nicotine cravings. Unfortunately, he decided he'd rather spend his time stealing his various hosts' knowledge before killing them by starving their bodies of nutrients and oxygen, then hijacking their bodies, each time forcing them to bite someone else and transfer him to a new host.
 * In Community episode "Epidemiology" Greendale becomes the epicenter of the outbreak for an experimental virus designed by the army.
 * Episode 5 of Danger 5 features a contagion that's turning the Allied soldiers into Those Wacky Nazis. Its source is a literal wellspring of the "Aryan seed"

Tabletop Games
""What’s worse to contemplate, though, is that we may get another major outbreak that spreads to multiple habitats before we can contain it. That might get very, very bad, very, very quickly.""
 * Dungeons and Dragons has the olive slime, yellow musk creeper, and probably other monsters of this kind. One prominent example is the vargouille; it's a relatively low-level monster (Challenge Rating 2) that reproduces by "kissing" members of another species. Unless this kiss is cured with an appropriate spell, over 24 hours, the victim's hair falls out, their head becomes more wrinkly, the ears grow and become wings, and eventually, the head separates from the body and becomes another vargouille. It was even more creepy in the first edition, when the separated head would still have a variety of internal organs attached, dangling down from the neck.
 * Also, the chaos beast could turn mortals into other chaos beasts. The Slaads can infect someone with their bites or their claws, placing Slaad eggs inside of the person, who'll eventually eat their way out, making new slaads.
 * And of course, many undead have the power to turn anyone they kill or Level Drain to death into an undead of the same kind under the control of their killer.
 * Mind Seed is one of the most insidious psionic powers in 3.5. Implant someone with a Mind Seed and it will slowly reshape the victim's mind- against their will or even without them noticing- into a mental replica of the psion at the time the power was used. Though the resulting personality will still have their own free will, the fact that it now shares the goals of the psion makes it incredibly effective.
 * Elder Evils, a sourcebook on all things Cosmic Horror, also gives this power to Sealed Evil in A Can Father Lymic, with the Brood created by him given a fraction of his Elemental Powers over ice. His goal is to ultimately corrupt the world, turning it into a Single Biome Planet of snow and darkness. Yeah, he's scary.
 * Despite his man-boobs.
 * GURPS has, at the least, Riders (from GURPS Aliens) and Valkryies (from GURPS Traveller: Alien Races 4 [I think it was 4]). Note that these are both ostensibly science-fiction (rather than fantasy or magical) species.
 * 4th Ed Ultratech has a metamorphosis virus that can be weaponized into either this or a version that turns everyone into random things, which can be much worse.
 * In Warhammer 40000, you have the insidious powers of Chaos, which can quite effectively turn the open mind into a willing cultist and a traitor to mankind.
 * You also have the insidious Tyranid swarms, the insidious Genestealer cults, the insidious Tau propagandists/brainwashers, the insidious Necron Pariah harvest, etc., etc., etc. Rarely is any given conflict zone in 40K NOT subject to some form of The Virus. Let's just say that in this universe, General Ripper typically has the right idea.
 * There's the dreaded Obliterator virus, which turns you into something truly horrific. The first tip that something horrible is going on is when you realise that you're spontaneously generating ammunition for your gun, which is becoming gradually more attached to your hand. From here, it's only a short trip to the point where you're an out-and-out psycho who can absorb guns, then create them again fused to your flesh.
 * Am I the only one who thinks that sounds pretty damn awesome compared to the fates of some Chaos cultists, especially those who fail (think living flesh bag of pain and get worse). Wouldn't mind being an Obliterator at all if not for the whole going insane bit.
 * Another electronic example is The Virus in Traveller: The New Era, originally designed as a weapon for shutting down the navigation systems of enemy warships in order to end the war without further bloodshed. Unfortunately the version that was prematurely unleashed when the research station working on it was attacked would shut down every computer in the vicinity through means unexplained (though heavily implied to be psionic in nature), with... interesting consequences if that computer happened to control (for instance) a nuclear reactor or a life-support system. Then it evolved full intelligence, which didn't improve matters.
 * One of Feng Shui's many Creature Powers is "Corruption", which allows a supernatural creature to infect others with their supernatural essence, and in this way create more of their kind. Corpse factories in the Glimpse of the Abyss supplement use a variant of this to create zombies for all your Zombie Apocalypse needs.
 * The short-lived Nightlife horror RPG had a race of borg-like monsters that embodied The Virus trope. Surprise, surprise, they were called "the Virus".
 * The premise behind the Cyberpunk sequel game, Cybergeneration.
 * Magic the Gathering gives us New Phyrexia, which is this, to the point of reprinting old cards with a Phyrexian twist.
 * This was pretty much Old Phyrexia's M.O. during the Weatherlight saga. it's pretty safe to say that this is Phyrexia's hat.
 * A legendary creature card from the Innistrad set, Olivia Voldaren, is a classic infectious vampire: one of her abilities deals a point of damage to a creature and turns it into a vampire, and her other ability allows her controller to take control of any vampire as long as she remains in play.
 * The Exsurgent virus family in Eclipse Phase. Different strains can infect computers...or flesh...and the result is never, ever pretty, usually featuring Body Horror and always featuring Mind Rape. Oh, and they're very, very adaptive. Like, normal-viruses-on-crack adaptive.

Theater

 * The opera Help, Help, The Globolinks! has invading aliens called Globolinks whose only known weakness is music. Humans touched by Globolinks are gradually transformed into Globolinks, first losing the ability to speak human language.
 * In Eugene Ionesco's absurdist play Rhinoceros, the townsfolk are all spontaneously transforming into rhinos.

Toys

 * The Makuta's virus and the Dreaming plague in Bionicle, although it's ambiguous as to whether the latter was actually transmitted virally or not.

Video Games

 * In Prototype, the character is The Virus. Under the right circumstances, The Virus gives a human being the powers to fly around and kill stuff with viral blades and whips and shit (as in the case of the main character); otherwise, you'll turn into a mindless, shambling, living zombie or a mutant with augmented speed and strength (as in the case of a lot of New Yorkers). It also infests warehouses (and ONLY warehouses for some obscure reason) to produce beefed up mutants that are incredibly annoying.
 * Only annoying until you get the blade air attack, which gets them consumable in two hits. Then they become a handy and valuable biomass source.
 * The Big Bad is the other virus, and because of her aggressive nature and the fact that Mercer's virus seems inert (read: non-transferable) in him after the initial infection, she's more dangerous anyway. Alex can't get half the bodycount she does unless the player's doing it on purpose.
 * Crysis 2 has a viral outbreak in Manhattan that may or may not be from the Ceph, and certainly wasn't mentioned at all in the original Crysis. A group called C.E.L.L. apparently is tasked with containing it at any cost...including the murder of any potential carriers.
 * Bacterion, Gofer, and Zelos of the Gradius series are incarnations of The Virus; Every time you defeat any one of these guys, the Bacterian cells that they are composed of will increase in numbers. Dr. Venom also applies to this too, since he's been modified by the Bacterians.
 * In Resistance: Fall of Man, an alternate history first-person shooter, the aliens known as the Chimera use a mutagenic virus that causes humans to fall into a coma and undergo horrific physical mutations that turn them into Chimera soldiers. These mutated soldiers retain no trace of their former personality and are completely subservient to the elite Chimera known as Angels; in fact, Chimera soldiers die if their psychic link with the Angels is severed.
 * In FOM, they needed a Conversion Center to fully complete the transformation in a reasonable amount of time. In R2, infected people simply have cocoons built around them and are left to transform on their own.
 * Appears in the War Craft series. The Lich King produces a virus which kills humans, then resurrects them as undead loyal to him. There is also a faction of Undead, the "Forsaken", who have broken free of the Lich King's control and have regained their free will.
 * The Flood in the Halo franchise, which latches onto sentient life forms, hijacks their body, mutates them horribly, and, when the host is no longer usable, uses it to incubate more Flood infection forms. The infection forms even look like macroscopic bacteriophages.
 * And when the Flood hijack enough bodies, they build a Gravemind; a giant, rhyming, Magnificent Bastard Hive Mind.
 * To make it even worse, the minds and memories are assimilated, and it's possible that the living mind of the victim gets assimilated (in backstory said MagnificentBastard has a habbit of bragging about transhumanism and ending suffering). This allows the Flood to, after a certain stage of outbreak, use any tool you can, if they can get their grubby tentacles onto it. Coupled with icky Body Horror and the assimilation and hacking of even spaceships, this Nightmare Fuel isn't too much of a stretch to imagine wiping out an entire pan-galactic civilization.
 * Which they are very heavily implied to have done before they arrived in the Milky Way galaxy and encountered the Forerunners.
 * Though it involves no physical changes aside from a possible pallete swap, the Maverick/ Virus from the Mega Man X franchise otherwise qualifies.
 * And after the Maverick Virus in Mega Man ZX
 * The Roboenza in Mega Man 10 is essentially a robotic equivalent of the flu. Except for the fact that it causes infected robots to go berserk for no real reason.
 * Left 4 Dead with the infection. In most cases the virus will turn most people into unintelligent "runner" zombies who will psychotically attack any uninfected individual. Body Horror comes into play when some of the infected mutate into special infected that feature warped bodies optimized for specific special abilities. The virus spreads by the infected transmitting bodily fluids (I.E. Getting bitten or being exposed to zombie bodily fluid), but it can also be spread by unknown means by Carriers, individuals who show no signs of infection but can spread the infection.
 * Sacrifice comic reveals that the virus mutates daily. One day it's airborne, nex day it's something else.
 * The Tuurngait virus in the Penumbra series: Able to infect pretty much everything. Causes the infected to become stronger and more resilient or just ridiculously huge, depending on species.
 * Final Fantasy VII had the Jenova cells. They started up a fairly innocuous power-boost, except in a few very specially treated individuals, who began to suffer from mad wanderlust and lose their minds. They then attempt to join up with the head of Jenova. Naturally, the main character, who was traveling all over the world for a reason he could hardly justify, based on little more than instinct, and seemed to suffer occasional but horrific mental episodes, turned out to.
 * Jenova's machinations go much further than this. According to Ifalna, in her interviews with Professor Gast, Jenova first landed on the Planet and began spreading its cells like a virus, mutating the Cetra into horrible monsters under its control. It seems that Jenova itself is an entity that travels from Planet to Planet, infecting the native inhabitants and transforming them into monsters that it uses to further spread its infection around, before bringing them all back and "reuniting" itself to travel to another Planet and continue the cycle. How long it's been doing this is anyone's guess.
 * The Super Mutants from the Fallout games were caused by The Virus; the first game culminated in the player destroying the transformation vats, although they could agree to be turned into a Super Mutant to achieve a Nonstandard Game Over.
 * Metroid Prime's Phazon is an example, but to very varying degrees, depending on the game and target.
 * In Prime 2, the Ing also have a tendency to take over the bodies of other creatures, both living and dead.
 * The X Parasites from Metroid Fusion are a more traditional version of this trope, as their only purpose is to infect more people.
 * Mass Effect 1 includes the . Also, there's . Both cases also involve instances where people choose to overcome the mind-control the only way they can.
 * To further fit this trope
 * The cyberzombies are a different kind. They are reanimated corpses.. This may or may not be intended as a failsafe.
 * The Sands of Time in the Prince of Persia trilogy work like this. Once released, they instantly turn everything they come in contact with into a crazed Enemy to All Living Things (living in this case being the few lucky souls who wern't instantly transformed). Somehow, when the Prince is exposed in the third game of the series, he manages to resist instant transformation, although he does still get a Super-Powered Evil Side.
 * The Corrupted, from the sequel, are an aversion-it's pretty much their own damnn fault they're Eldritch Abominations now.
 * The R-Type series eventually evolved the Bydo into something like this, although this isn't their favored modus operandi: usually, they simply evolve, replicate, and reproduce to improve themselves and strengthen their numbers, but given the opportunity, they will assume forms that are designed to infect and assimilate enemy technology and personnel. R-Type Delta had a good example of this in several of its ships and one of its Multiple Endings, and R-Type Final and R-Type Tactics/Command use this as a turning point in their respective storylines (much more the latter, with it even affecting gameplay).
 * In Overblood it's called the ARNA Virus and Raz has it.
 * Resident Evil is replete with these, both in the form of literal viruses, and the Las Plagas parasites.
 * Knights of the Old Republic has rakghouls, deformed mutants with infectious bites, living in the Undercity of Taris. The player character cannot be infected, but several infected NPCs are seen transforming. In some cases it can be prevented with a dose of rakghoul serum, but once the victim has actually been transformed they must be killed. Interestingly, when the player character or a party member is bitten, they can be poisoned and take standard poison damage, and there is an instance where you save an NPC and he has been bitten and poisoned, but no one comments on this. This may mean that the rakghoul disease can be avoided outright if treated immediately.
 * In the comics, it was revealed that the rakghoul disease was concocted by a Sith who made a talisman that instantly transformed humans into rakghouls which he could control, getting them to use their old skills, like weaponry. Comics taking place between the movies of the original trilogy had a fallen Jedi using this talisman on various heroes, including a member of The Remnant.
 * Extermination revolved around this. The Virus would mutate and corrupt pretty much anything to do with water. The player probably would freak out about the time a puddle of water actually attacked/infected him. Getting 100% Infection and not curing it fast leads to a Nonstandard Game Over where the player watches the transformation into a monster...
 * The Beast subversion entity from the first Homeworld sequel certainly counts. It quite literally rips its host apart, extracts their neurons, and then sets about using them to form an organic computer network it can subsequently use to control the ship they were flying, and hence infect more vessels. The quote formerly at the top of the page comes from the initial cut-sequence describing the entity -- spoken by a poor engineer who sounds like he either wants to throw up or cry just about all the way through.
 * Ordinary Beast entities have an animalistic behavior and only care about multiplying. The original entity inside the Naggarok however, is very much sentient: when the Imperialist Taiidan make first contact with it, the entity offers them half the galaxy if they repair the Naggarok's drives. It also tricks them into believing that the Bentusi are gone and that they will get the Nomad Moon. When the Moon is infected and is subsequently destroyed by the Somtaaw who in turn receive aid from a Bentusi ship, the Imperials flip out and turn against the Beast; cue the Naggarok calling in all of it's "children" to catch the Kuun-Lan from three sides.
 * Silpheed has get taken over by an alien virus and turns into not only an enemy alien, but also That One Boss.
 * The old Area51 lightgun game revolves around an alien virus being unleashed and causing a Zombie Apocalypse in the area. The Game Over screen shows a video of the protagonist morphing into one of the alien mutants.
 * Dead Space 's Necromorphs are unique in that only one of its forms is The Virus and it can only infect dead people. It's the task of the other Necromorphs to ensure there are dead bodies to infect.
 * the Virus can somewhat infected people but only after weeks of being in contact with the source, drive them insane and kill themselves, after a few more hours the virus takes effect. The infector verson just speeds up the progess form 10 hours to 10 seconds.
 * One of the glitch Pokémon is Charizard 'M. From the entry at Bulbapedia: "Charizard 'M can also change all of a player's party Pokémon into Charizard 'M, but the moves and type do not change, and putting these "transformed" Pokémon into a box makes the other Pokémon Charizard 'M also."
 * For that matter, the Pokémon series has an actual gameplay mechanic called the "Pokérus", which your Pokémon can pick up randomly during the game. This isn't a bad thing by any means though, and actually helps your Pokémon get stronger stat boosts when they level up. It also wears off after a few days.
 * They stop spreading it after a few days, that is. Any Pokémon that's ever had the virus will retain the speedy growth forever. It also "freezes" when the Pokémon's in a box, allowing you to keep a few virus-spreaders handy for when you need to infect more of your mons.
 * Yamask and Cofagrigus's ability, Mummy, is this. When it is touched by the opponent their ability turns to Mummy.
 * Star Fox Assault has the Aparoids, a robotic insect colony from another dimension that infects both biological creatures and mechanical objects.
 * Alma does this to Sergeant Keegan in F.E.A.R.: Project Origin, using her psychic powers to literally make him fall in love with her. The only way to save him is to kill him.
 * For a technological example: the unnamed computer super-virus from Descent, which takes over mining robots and turns them against humans, while at the same time drastically increasing their AI. It's much more powerful in the novel adaptations, in which the virus can take over just about any machine and give it sentience, and possesses AI of its own, allowing it to intelligently react to and avoid anti-virus measures.
 * The Strange Virus from Puzzlebox boosts a person's resilence to injury, inspires creativerty and sends its hosts mad.
 * In the Elder Scrolls: Morrowind, corprus if caught turns non-believers into zombie-like creatures and believers into strange powerful deformed beings.
 * The Zerg from Starcraft, obsessed with assimilation into the swarm, pretty much embody this trope. More obviously, they can also infest Terrans (who either are Suicide Bombers or become Queen Bitch of the Universe).
 * In the Starcraft II mission "Outbreak", it morphs them into straight-up zombies, complete with moaning "Please... Kill Me..." the multiplayer/skirmish Infested Terrans lampshade it, complaining of "being under the weather" or "having caught something".
 * Emperor: Battle for Dune. The Contaminators, mutants spawned from Tleilaxu Flesh Vats. They carry a lethal virus capable of turning humans into additional Contaminators. There's also the non-human variant called the Tleilaxu Leeches, biogenetic tanks that create replicas of themselves by implanting larva in enemy vehicles, which damages the host vehicle until it's destroyed before hatching into another Leech.
 * The Bydo from R-Type is probably one of the most horrifying version of this when you think about it hard enough. Due to their nature, they can turn themselves into a wave, meaning they can bypass any sort of protection without notice before they start taking over and can also take over machines with ease as well.
 * The Darkspawn taint in Dragon Age Origins. The Darkspawn spread this disease wherever they go, turning any living things that are exposed to it into horrible monsters. Yes, this includes people. The taint unites the Darkspawn in a primitive Hive Mind, though only an Archdemon, a draconic Old God corrupted by the Darkspawn taint, can unite all of the Darkspawn hordes. That's right, this particular Virus can corrupt gods.
 * Both System Shock and its sequel feature enemies infected by The Virus. In the first game the hybrids are subservient to SHODAN, but in System Shock 2, they're controlled by the Hive Mind of "The Many".
 * In Strife, the virus arrived via a massive comet impact. Those who weren't wiped out begin to mutate, hearing the voice of an alien monster and causing their bodies to rot. The Evil Empire Religion of Evil that worships the monster uses cybernetics to maintain their self-destructing bodies.
 * The A-Virus in Disgaea 4 a Promise Unforgotten is a humorous take on the trope, but nonetheless horrifying in its own way.
 * Overlord has an example of the "turns the victim into a mindless shambling zombie" type. The interesting part is how it spreads:
 * The virus blocks in Astro Pop. They can't be grabbed, and you can only get rid of them by making a match next to them. They also "infect" other blocks, turning them into more virus blocks. You can interrupt the transformation if you grab the block before it's transformed.

Webcomics

 * The revenants in Girl Genius. A bioweapon devised by a mad scientist, the revenants are produced by devices called hive engines. When activated, the devices release a queen "Slaver Wasp" that almost immediately produces hundreds of soldier wasps (insectoid, non-flying killing machines the size of a big dog). They then make a perimeter and drive everyone inside to the center, where the queen releases a horde of tiny wasps that fly down your throat and control your brain. These newly created revenants act as zombie guards for the hive while the warriors corral in more humans. Additionally, the revenants are completely loyal to the creator of the hive engine, making them an excellent device for assembling instant armies of mooks.
 * The Dimension of Pain demons from Sluggy Freelance possess a spear that can turn human beings (and ferrets, apparently) into demons, and they use it frequently during their invasion of the Dimension of Lame. However, since the spear can't completely get rid of the humans' inherent wussiness, the result is an army of pretty wussy demons.
 * A human-made version (or is it...?) has appeared in the main dimension now. None of the resulting demons has been seen for more than a strip or two, so it remains to be seen if the results are Lame or otherwise weaker than real demons.
 * The Legion from MSF High are a legion of Green Skinned Space Babes who, when forced to fight, turn their attackers (whether male or female to begin with) into Green Skinned Space Babes who see things their way. That's in the present; they worked similarly in the past, but replace "attackers" with "defenders" and "see things their way" with "lose all of their original personalities and fight mindlessly for the Queen."
 * The Dragon Doctors face their first real challenge when attempting to cure a patient who has a "Crax Parasite" inside him, a horrible, cancerous growth that will eventually consume his body and mind. The four magical doctors each make use of their full abilities to cure the disease. Kili the shaman occupies the patient's mind in a dream world while the others operate, and it is revealed when the Crax invades the dream that it's the vehicle of the consciousness of a man who wants to live forever.
 * In Superidol computer-generated idol Rei Rei is the memetic version of this, with billions doing everything they can to be her, until the whole world revolves around her.
 * This Cyanide and Happiness strip.
 * Zombie Waffe has LARS (Likasi Acute Rabies Syndrome) a new form of rabies which turns those infected into zombies.
 * Unity, one of the protagonists of Skin Horse, is a non-virulent virus. She's a collection of nanobots suspended in fluid, and anything injected with her becomes her completely... but she can't actually fight off the immune systems of the living at all, so anything not dead she tries on ends up vomiting her out after a short while. And she has no method of spreading outside of purposeful injection.
 * The Kingfisher is a vampire comic in which the condition can be communicated. It usually doesn't affect the mind of its victims directly, unless they become too hungry for blood.

Web Original

 * The Global Guardians PBEM Universe included the aptly named Virus, a villain who takes control of people using a tailored genetic infection that slowly transforms them into copies of itself. Its ultimate goal is to make all life on earth a copy of itself.
 * The Infestation of The Nutty Joes. A giant brain crash lands in the middle of a quiet country village, hatching a crazed creature whose laughter soon rings out throughout all of mankind.
 * The SCP Foundation have a dossier on SCP-217, which is basically The Virus plus Clockwork Eats Your Soul.
 * Whateley Universe examples: The Palm is a living artificial intelligence in the internet, trying to replicate and wipe out all human life. In a much creepier variant, in the story "The Op", this is what the heroes face, complete with Body Horror and Womb Level.
 * The Computer Virus from We Are Our Avatars. In the past, it's infected many of the robotic characters, and most likely counts as Nightmare Fuel.
 * In the Prolecto series of stories, found here: http://www.furaffinity.net/view/6721353, this is how the Succubus transformation spreads. in a subversion, people are GENERALLY pretty much themselves...except for the compulsion to spread. Which wears off after they spread once, unless they take a deep breath. Unfortunately, at least one of them has Contractual Genre Blindness. Hilarity Ensues.

Western Animation
"Robot: Is it true, humans sneak into your room at night, drain your fluids, and turn you into a human?"
 * Baron Dark from the cartoon Skeleton Warriors could change anyone not "pure of heart" into a Skeleton Warrior.
 * The Skeleton King from Super Robot Monkey Team Hyperforce Go does not have that restriction for making zombies.
 * Beautiful joke example from The Tick: when reminiscing about past adventures, Captain Decency remembers the time a villain built a superweapon known as the "Ray Gun". This gun functioned by turning anyone it shot into a duplicate of "some guy named Ray", depicted as a gas station attendant with the nickname "Ray" on his coveralls. Cue incredibly creepy Twilight Zone-style black-and-white shot of a town filled with identical Rays saying "Hi, I'm Ray!" to each other over and over. Captain Decency then begins to reminisce about a similar adventure involving a "Tommy Gun" before being cut off.
 * In The Pirates of Dark Water, the eponymous Dark Water had the ability to kill people outright, or corrupt them into mutated minions or mindless slaves. In one of the more Nightmare Fuel-laden episodes, an elderly woman tries ingesting a drop of it in a youth potion and it winds up consuming her completely from the inside.
 * Daemon was a literal software virus in Re Boot as were Megabyte and Hexadecimal. Daemon and Megabyte match this trope better as they had the ability to infect the system's sprites and convert them into their loyal soldiers.
 * In Code Lyoko, some of XANA's attacks follows this route, the specter first possessing one animal then spreading the control to others (rats in "Plagued", wasps in "Swarming Attack"). In "Attack of the Zombies", a possessed Kiwi can transmit The Virus to humans, Zombie Apocalypse-style.
 * A robot from a planet of robots fears humans are The Virus in the Futurama episode, "Fear of a Bot Planet".

"Hermes: The flight had a stopover on the Brain Slug Planet. Hermes liked it so much he decided to stay of his own free will."
 * Also, don't forget the Brain Slug.


 * Played for laughs in an episode of Camp Lazlo. It's learned in this episode that when Samson gets sick, his germs can cause others to at first, get sick, and then end up looking a lot like a hamster who is sick,
 * The Xenocites from Ben 10 Alien Force, when placed on a carbon-based lifeform, transform them into a DNAlien under the thrall of the Highbreed.
 * The nanite hive from the Alien Swarm movie is another example.
 * The original Transformers has the Hate Plague from Outer Space which was unleashed upon the Earth. At first it appears to make those infected fight others and themselves, but later on it just appears to make them act like jerks with the intent of infecting others. Either way, the last known hope to the world, nay, universe is to revive Optimus Prime. It works, of course, and even Galvatron is thankful enough to call for a truce. For now.
 * Previously in the same season, the Transorganic energy-leech threatened to spread the robotic equivalent of vampirism to all of Cybertron.
 * Much later, in Beast Machines, technomatter made with the Key to Vector Sigma had much the same effect - when the Maximals were zapped with the Key, they became both contagious and mentally unstable, and tried to infect each other.
 * In the Generation One Continuity, Megatron creates a transmitter called the "Crimson Fog" to magnify the disharmony and hostile behavior between Transformers.
 * An episode of Samurai Jack, "The Aku Infection", dealt with Jack being infected by Aku's spirit, which began to transform Jack into Aku from within. Jack had to defeat Aku in a Battle in The Center of The Mind to purge him, drawing on his experiences and the good he's done in the future for power. Aku never stood a chance.
 * The Fudd from Duck Dodgers, a parody of the Flood which transformed people into goofy-looking bald men with speech impediments.

Real Life

 * Of course, viruses. They tend to do it on a microscopic scale; a popular method is for a virus to inject its genetic material into a cell, which corrupts/mutates it, making it produce more viruses inside itself. It then bursts, spreading many more viruses throughout the body and killing the cell in the process.
 * Bacteriophages work the same way - being viruses that target bacteria.
 * Ebola does the same thing. Only to humans, at the human level. Sephen Preston's The Hot Zone Provides graphic descriptions of what it does to its host. The scariest damn book I ever read - I'm a fan of Michael Chrichton, too - and The Hot Zone is NONFICTION. (Shudder)
 * Speaking of viruses: Rabies. It infects your brain, drives you mad, uses you to spread the disease, and kills you once it's done with you. Yup, a real-world equivalent of the Rage.
 * Fortunately it tends to kill within a week of showing symptoms, so your chances to spread it are limited.
 * In some languages, HIV/AIDS is referred to simply as this.
 * Prions are proteins that act as The Virus to other proteins, converting them into prions. This can also become The Virus for organisms, if the proteins being converted happen to be located in the brain.
 * Diseases can alter your behavior in ways to spread themselves, but you may not realize it. Malaria makes you too tired to fight off mosquitos, for instance.
 * Defensive reflexes designed to rid our bodies' airways of infection (coughing, sneezing) are also behaviors that tend to spread it to others.
 * Some real-life Puppeteer Parasites do this. Some require one host to carry, and another host to reproduce in, and force their primary host into zombie-like behavior. Some even have ants climb onto grass stalks overhanging their hives and emit spores as they decompose to infect healthy ants. Sounds like Resident Evil 4 meets A Bugs Life, doesn't it?
 * If certain theoretical conditions are met, stable strangelets -- a hypothetical category of subatomic-scale particle -- could convert any normal matter they contact into more strangelets, which could then go on to convert more normal matter, and so on.