History Main / TheVirus

* ''VideoGame/ProjectZomboid'' has the Knox Infection, the mysterious contagion responsible for the ZombieApocalypse. The infection is spread through bodily fluid contact. In-game, players can contract the disease either through injuries sustained from zombie attacks, but infection is not shown as a status ailment in the same way as a cold or infected wound: players will need to monitor their health after sustaining injuries from fighting a zombie, and take appropriate action as the situation dictates.[[note]]Scratches have a 7% chance of spreading the infection, while lacerations have a 25% chance. Bites, on the other hand, are 100% guaranteed to spread the disease.[[/note]]

* ''VideoGame/{{Extermination}}'' revolves around this. The Virus mutates and corrupts pretty much anything to do with water. The player will probably freak out about the time a puddle of water actually attacks/infects the player character. Getting 100% Infection and not curing it ''fast'' leads to a NonStandardGameOver where the player watches the transformation into a monster.

Sometimes overlaps with BodyHorror in cases where the host enters a zombie-like state before being completely consumed. Compare ViralTransformation, where a similar change ''does not'' cause a FaceHeelTurn. See also PuppeteerParasite, FesteringFungus, CloneByConversion, FaceFullOfAlienWingWong, ContagiousAI, MindVirus, FisherKingdom, MonsterProgenitor, TheCorruption, TheAssimilator and ZombieApocalypse. Commonly represented with TaintedVeins or a RedRightHand. Nearly always a SnowballingThreat as it accumulates victims. When the virus itself is portrayed as a miniature monster, rather than turning its victims into monsters, it's MonstrousGerms.

** [[http://scp-wiki.wikidot.com/scp-008 SCP-009 ("Zombie Plague")]] is probably the simplest and most [[ExactlyWhatItSaysOnTheTin self-explanatory]] example. It's a prion disease that turns people into [[FleshEatingZombie flesh-eating zombies]].

* ''VideoGame/MortalKombat1'' reimagines the Tarkatans (a race of [[MoreTeethThanTheOsmondFamily excessively fanged]] barbarians with [[BladesBelowTheShoulder arm blades]]) as Outworlders suffering from a disease called Tarkat. It mutates them into the series' iconic Tarkatan form, arm blades included, and gradually degenerates the afflicted's mental state until they become blood-crazed savages. While it is unclear how the disease is transmitted, Baraka's physical appearance alone gives a good example of just what damage it can do to anyone who contracts it. Mileena spends most of the game's story affected with its early stages so she retains a pretty outward apperance, apart from her mouth at times turning to its series-iconic monster maw. Those caught afflicted the disease are stripped of any titles and honors kicked out of Outworld society and forced to live in squalid colonies to avoid spreading the infection all over Outworld. There is a serum that can temporarily stop Tarkat's manifestation but no outright cure for it exists, hence Baraka considering [[DeathSeeker death the only release he and his fellow infectees can hope for.]] Part of their stories is how Tarkat has affected their lives; Baraka was once a famed merchant and tribune before he contracted Tarkat and lost everything, and a large part of Mileena's story is her and her family trying to avoid letting her suffering the disease become public knowledge, or else los eMileena her inheritance of Outworld's throne.

* except Reston was an airborne virus unlike human infecting versions, that was why it scared the shit out of scientists who did not know at the point that the virus was non lethal, it was still capable of infecting humans (workers at the site tested positive for Ebola virus anti-bodies) its just they were not symptomatic.

** Kuru: a real disease that leads to ''zombification'' and eventual death.
*** It's even caused by eating brains! However, the actual symptoms of Kuru are only superficially "zombification". Spread by consuming the body of someone with the disease, Kuru causes the victim to slowly lose co-ordination and muscle control until they can't even sit upright without assistance, eventually killing them through malnutrition (they often lose the ability to swallow) and secondary infections. It also has an incubation period of around a decade, and is totally incurable.

The Virus turns people [[TheAssimilator into itself or into entities subservient to itself]]. The transformation is both [[{{Brainwashed}} mental]] and [[ViralTransformation physical]]. The converted will have unflagging loyalty and be instantly ready to commence villainous actions. Expect it trying to cause ThePlague.

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

Sometimes overlaps with BodyHorror in cases where the host enters a zombie-like state before being completely consumed. Compare ViralTransformation, where a similar change ''does not'' cause a FaceHeelTurn. See also PuppeteerParasite, CloneByConversion, FaceFullOfAlienWingWong, ContagiousAI, MindVirus, FisherKingdom, MonsterProgenitor, TheCorruption, TheAssimilator and ZombieApocalypse. Commonly represented with TaintedVeins or a RedRightHand. Nearly always a SnowballingThreat as it accumulates victims. When the virus itself is portrayed as a miniature monster, rather than turning its victims into monsters, it's MonstrousGerms.

* ''Manga/VenusVersusVirus'': The Virus changes humans into demons.

%%* This happens to ''entire planets'' in the ''[[VideoGame/{{Gradius}} Salamander]]'' OVA.
* ''Anime/DigimonAdventure02'': The Dark Spores are spread by Milleniummon to harvest the darkness in people's hearts. It's effects are closer to MoreThanMindControl than traditional but victims still turn into {{smug snake}}s.
* ''Manga/BlueDrop'' has a somewhat lesser example. The second manga, ''Tenshi no Bokura'', implies that any human female sexually exposed to the OneGenderRace Arume (a species of alien lesbians who reproduce by a complex-and-imperfect genetically engineered HomosexualReproduction process) becomes 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.
* In ''Manga/{{Guyver}}'', the Zoanoid Aptom eventually gains the ability to infect other Zoanoids, then absorb their biomass, and is able to make duplictes of himself.

* ''Anime/LeChevalierDEon'': 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.

* ''Manga/WorldEmbryo'' has the Kanshuu. 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.
* ''Manga/JoJosBizarreAdventure'':
** ''[[Manga/JoJosBizarreAdventureStoneOcean Stone Ocean]]'': After Weather Report regains his memories, his Stand transforms into Heavy Weather that subconsciously creates rainbows that contain subliminal messages making people who look at the rainbows and touch them turn into snails. The transformed snails also actively seek out other living organisms and contact with a snail also initiates the transformation.
** ''[[Manga/JoJosBizarreAdventureSteelBallRun Steel Ball Run]]'': Ferdinand's Scary Monsters lets him transform people and animals into dinosaurs by touch, and anything that the dinosaurs wounded will also turn into a dinosaur, a process that can be infinitely recurring.

* In ''Literature/TheExecutionerAndHerWayOfLife'', Machine Society's Pure Concept "Vessel" works this way. It attaches to people and slowly overwrites their bodies with the power of Pure Colors, eventually erasing their identities entirely and turning them into empty shells which become extensions of Machine Society.
* ''Anime/GaoGaiGar'': Zonder Metal, which can corrupt organic lifeforms as well as cyborgs and sentient AI into mechanical monsters.
* The ''Anime/CardfightVanguard'' manga introduced a superpower known as [=PSYqualia=] that was later exploited by the BigBad to transform people into "[=PSYqualia=] Zombies" under his control. The virus was spread via Cardfights, as being defeated by a [=PSYqualia=] Zombie would transform the loser into another Zombie, giving them a SuperpoweredEvilSide with a side of BrainwashedAndCrazy. The goal of the BigBad was ultimately [[spoiler:to exploit [=PSYqualia=]'s control over destiny by creating a critical mass of Zombies under his control, then using their collective gravitational power to rewrite the laws of the world itself]].
** The anime (which at the time had OvertookTheManga) introduced its own version during the ''Link Joker'' arc called "Яeverse". Like "[=PSYqualia=] Zombies", the Яeverse virus spread through Cardfights and slapped their victim with a BrainwashedAndCrazy SuperpoweredEvilSide and subservience to the BigBad of the arc. The real-world card game mirrored this storyline through the introduction of corrupted "Яeverse" versions of existing cards, which depicted the corruption with varying degrees of UnwillingRoboticisation.

** The "Legion of the Damned" arc in ''ComicBook/LegionOfSuperHeroes'' post-''Zero Hour'' features the Blight, which ravages the [[TheFederation United Planets]] and takes over most of the Legion before the remaining Legionnaires manage to purge it.

* The comic book series ''ComicBook/{{Powers}}'' had an arc that revolved around a dangerous and addictive superpower, ([[DrugsAreBad can anyone say drug addiction allegory?]]) that was spread between people, infecting new users.

* In the French comic ''Zombillenium'', an amusement park run by monsters has a staffing problem. Two managers (a werewolf and a vampire) bite a new guy so he can fill a gap as that monster, but as they keep arguing over who gets him they also keep on biting him to assert their hold. He ends up turning into a BigRedDevil instead, and ends up being the star attraction.
* The second major arc of ''ComicBook/SonicTheHedgehogIDW'' is about [[BigBad Dr. Eggman]] unleashing a virus that turns the infected into [[UnwillingRoboticisation robotic zombies, or "zombots"]]. It's designed to speed up the infection rate with further physical contact [fighting zombots] and is extremely contagious on any organic matterial by a simple touch. [[spoiler: Sonic himself is infected, and a major part of the arc is him trying to fight the transformation's spread.]]

* In ''Fanfic/ProjectTatterdemalion'', a SciFi/horror AU of ''Manga/{{Bleach}}'', Hollows are the result of an alien SyntheticPlague 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 CombatTentacles and a drive to infect others to reduce their loneliness. The other eighty percent die messily from the incomplete effect. There is a vaccine but it has side effects.
%%* ''Fanfic/MegaManRecut'' has Roboenza in "Robosaur Park."
* The ''Literature/{{Animorphs}}'' fanfic ''[[Fanfic/{{Eleutherophobia}} The Thing from Another World]]'' centres around a crashed [[TheGreys Skrit Na]] ship. [[spoiler:It turns out that everyone on board was killed by an alien pathogen that causes people to become violent cannibals. When Tom and the Animorphs enter it to investigate, Marco gets infected.]]
* ''Fanfic/FelixsGuideToApocalypseSurvival'' is centered around this, with [[GameMod Carol]] creating a pathogen that turns people into clones of herself. No surprise, considering that this was inspired by [[https://www.deviantart.com/jackson-tfs/art/TG-TF-Carol-Twinning-878431710 two]] [[Film/TheMatrix things]]

* ''Franchise/{{Alien}}'': The black liquid Chemical A0-3959X.91 – 15 featured in ''Film/{{Prometheus}}'' and its direct sequel ''Film/AlienCovenant''. It's described as a pathogen that infects viable hosts and produces hybridized predatory monsters like the Neomorphs, who themselves come out of spores that insert themselves into a host's body skin via OrificeInvasion. The pathogen was specifically designed by the Engineers to ultimately eradicate all fauna in a planet's biosphere while leaving the flora untouched. The ''Covenant'' novelization goes into greater detail, with David saying that Neomorphs — like the Xenomorphs — inherit traits and abilities based on their host species.

* ''Film/DayOfTheDead2008'': The Wildfire virus which creates the [[FleshEatingZombie Flesh-Eating Zombies]] is apparently airborne, causing victims to at first develop flu-like symptoms, then zone out before turning, although bites can also infect people who the airborne strain doesn't get to. Fortunately, you're only a mortal threat to your loved ones if you ate meat — if you're a vegetarian, not only will you make a docile zombie, but you'll remember people you had a crush on (or at least, you'll remember having a crush on them) and even try and defend them from other zombies.

* ''Franchise/TheMatrix'': Agent Smith in the sequels. After Neo tried to delete him, he comes back and can now copy himself into other people. It's ironic, given that he was disgusted by the human race and called them a virus in the first movie. Also, for symbolism points, his [[CoolShades sunglasses]] changed after his resurrection. Originally, they were square; now they're slightly more rounded, and have the general shape of a protein capsule of most viruses. Throughout the 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' FridgeBrilliance.

* As the name implies, the antagonist from the 1999 film ''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''.
* ''Film/VirusShark'': The driving force of the movie is finding a cure for [=SHVID=]-1, an obvious {{Expy}} of [[UsefulNotes/COVID19Pandemic [=COVID=]-19]] that was discovered in sharks.

* Vampires. It is a standard feature of their mythos that they turn others into vampires by biting them. Some modern variations, however, change it slightly so that one must drink the blood of a vampire to become one, thus getting around the conundrum of why there isn't a [[ZombieApocalypse Vampire Apocalypse]] in such stories.
* Werewolves, in more modern versions, turn others into werewolves by slashing and biting.
* Zombies are complicated. Depending on the verse, it could be a bite, a chemical, a magic spell, etc.
** Or even nothing at all; the "classic" zombie of pre-Hollywood folklore is simply a corpse raised by a presumably evil magic-user of some stripe or other to do its master's bidding and lacks the raw ''ability'' to inflict its own condition on others. (It may still kill you, of course, but you're not going to get up again as a zombie yourself under your own power afterwards.)
* That most dreaded and contagious of schoolyard infections: Cooties!

* The Infection in ''Literature/AnOutcastInAnotherWorld'' only affects animals, and horribly mutates them. The longer an animal has been affected, the worse the mutations get, to the point that they become borderline {{Animalistic Abomination}}s.

* In ''Literature/{{Cujo}}'', the virus in question is [[RealLife rabies]]. A [[BigFriendlyDog St. Bernard]] is bitten on the nose by an infected bat and turns into an insane killing machine in as little as a week from initial infection. There is some ArtisticLicenseBiology involved here: rabies has an incubation period of around one to three months, [[spoiler:and when Donna is bitten and infected later, she begins to show signs of primal rage from early onset; the violent tendencies shown in infected animals do not usually manifest in humans in the same way, and besides, while post-exposure treatment before symptoms is thankfully nearly 100% effective, after symptoms treatment effectiveness is radically reduced and survivors still usually have severe neurological problems for the rest of their lives.]]

* ''Literature/EdenGreen'' follows the spread of an alien needle symbiote that renders its hosts immortal; the title character is on a mission to learn how to destroy it and prevent further infection.

** In ''Literature/DeathTroopers'' 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.
** ''Star Wars'' zombies are nothing new, though in their ''Literature/GalaxyOfFear'' appearance they [[OurZombiesAreDifferent don't bite and aren't infectious]]. However, ''The Planet Plague'' does have {{Blob Monster}}s that creep about and, on skin contact with people, infect them with viruses that turn ''them'' into blob monsters.

* Jasmine from Season 4 of ''Series/{{Angel}}'' turns everyone into her fanatical worshipers willing to kill others for trying to free them from her influence. Ironically, being infected with her blood frees you from her control. Jasmine refers to it as "spreading the hate".

* ''Series/BuffyTheVampireSlayer'':
** ''Buffy'' vampires have their previous selves' souls replaced with a [[MonsterFromBeyondTheVeil demon]] (though it can be [[Series/{{Angel}} retrieved later by a spell]]). This is 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. 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:
--->'''Willow:''' It's horrible! That's me as a vampire? I'm so evil and... skanky. And I think I'm kinda gay.\\

'''Angel:''' Well, actually... (''sees Buffy's [[DeathGlare expression]]'') ... That's a good point.
** Angel's response reveals that the common explanation for vampirism doesn't ''quite'' work for all vampires. In ''Series/{{Angel}}'' when Angel's soul is again lost and the gang attempt to put it back, Angel has the chance to interact with his "alter ego" Angelus via a drug-induced dreamstate. Angelus puts it to Angel that they are simply two sides of the same person rather than literally being two distinct personalities, since Angel is perfectly capable of exactly the same kinds of vicious acts. "Angel" just regrets it afterward.
** In "[[Recap/BuffyTheVampireSlayerS2E12BadEggs 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.

* In ''Series/{{Community}}'' episode "[[Recap/CommunityS2E06Epidemiology Epidemiology]]" Greendale becomes the epicenter of the outbreak for an experimental virus designed by the army.
* Episode 5 of ''Series/{{Danger 5}}'' features a contagion that's turning the Allied soldiers into ThoseWackyNazis. Its source is a literal wellspring of the "Aryan seed" [[spoiler:and it is sexually transmitted. Exposing it to Swiss blood is the antidote, since in the Dangerverse, [[ArtisticLicenseBiology Swiss blood is... made of gold...]]]]

** "[[Recap/DoctorWhoS27E9TheEmptyChild The Empty Child]]"/"[[Recap/DoctorWhoS27E10TheDoctorDances The Doctor Dances]]": The titular Child is [[spoiler:a little boy raised from the dead by alien medical {{nanomachines}} that have no clue how to rebuild humans. Any time he touches someone, the nanomachines reprogram them to the way they think all humans should be — down to the gasmask and injuries the boy had when they found him]].

* In ''Series/{{Helix}}'' two strains of SyntheticPlague have jumped from lab animals to humans during a viral outbreak. Unlike NARVIK-A, which causes hemorrhagic shock and eventually liquefies its victims, NARVIK-B, the mutated strain, does not kill its victims, but instead modifies their behavior so they become [[SuperStrength super-strong]], paranoid, aggressive and biologically driven to infect others via forcible transmission, which entails assaulting and restraining victims and [[BadBlackBarf vomiting a black secretion]] into their mouths.
* ''Series/{{JAG}}'': Sudanese Ambassador Moshak in "Embassy" stole vials of Ebola from a U.S. military lab, and when Harm is about to get him, he throws a vial of Ebola at him. Fortunately Harm caught it.

* ''Series/LetTheRightOneIn'': In the series vampirism is explictly the result of a virus that any person who's bitten will become infected by (assuming they survive).

* "The Sickness" from ''Series/{{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 [[spoiler:Claire and Sayid]] become infected, start following the orders of the BigBad and kill a whole bunch of people.
* ''Series/TheOutpost'' features this as a major threat in Season 3. The season's BigBad, [[spoiler: Priestess Yavalla]], comes into possession of the white kinj, which can self-replicate and pass the offspring kinj into other people via physical contact, linking them into a HiveMind (known as the United) dominated by the original host. This is treated very much like a plague outbreak by the non-United, including referring to the United as "infected" and turning the outpost into a quarantine zone to try and keep the United out.
* On ''Series/PowerRangersInSpace'' there was the Barillian Bug, an insect-like MonsterOfTheWeek created by Darkonda with a sting that could turn people into monsters like itself, who had the same sting. Darkonda had intended to use it this way, but it only infected Carlos and Cassie before an antidote was found and the actual Bug was destroyed.
* The fungus from ''Series/{{Primeval}}'' takes root in human skin, eventually taking over the brain and transforming the host into a bizarre killer fungus creature.

* ''Series/StargateAtlantis'':
** Inverted where the good guys invent a virus that turns enemy Wraith into docile, submissive humans. 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.
* ''Franchise/StarTrek'' "We are Borg. You Will Be Assimilated. Resistance is futile." In some shows they inject "nanoprobes" into their victims (which rewrite the victim's DNA and cause them to grow Borg implants), and in others it's a more involved process that includes surgery. In ''Film/StarTrekFirstContact'', the Borg use both nanoprobes to convert ''Enterprise'' crew into Borg drones and surgery to graft tools and scanners to the drone body.
** The Borg's "assimilation tubules", which introduced nanoprobes into the series and made the Borg more this trope, appeared for the first time in ''Film/StarTrekFirstContact'', suggesting in-universe that they had assimilated this technology from one of their conquered species.
** In the episode "[[Recap/StarTrekTheNextGenerationS6E12Aquiel Aquiel]]", the ''Enterprise''-D also encounters a "coalescent organism" which kills someone and then replaces them. By the time they realize it, Geordi nearly becomes its next victim.

* ''Franchise/SuperSentai'': A key trait of Dezumzorya, the BigBad of ''Series/BakuryuSentaiAbaranger''. It combines physical infection with MoreThanMindControl to great effect.

[[folder:Podcasts]]
* In ''Podcast/TheMagnusArchives'' characters start finding strange silver worms. It becomes apparent that these are controlled by [[spoiler:Jane Prentiss]], and infest people and either kill them or turn them into zombie-like servants (or both).
[[/folder]]

[[folder:Radio]]
* The ''AudioPlay/BigFinishDoctorWho'' villain The Eminence, a DeadlyGas being that kills anyone who breathes any part of it in and converts them to a soulless, deathless soldier impervious to damage.
** The War Doctor audios have the Vaarga Plants return, now with the ability to turn Time Lords as well - and even regeneration won't save them.
[[/folder]]

* ''TabletopGame/Warhammer40000''
** Powers of Chaos, which can quite effectively turn the open mind into a willing cultist and a traitor to mankind.
** [[HordeOfAlienLocusts Tyranid]] [[ExtremeOmnivore swarms]], the insidious [[FaceFullOfAlienWingWong Genestealer]] cults, the insidious [[ScaryDogmaticAliens Tau]] propagandists/brainwashers, the insidious [[OmnicidalManiac Necron]] [[HalfHumanHybrid 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, GeneralRipper typically has the right idea.
** 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. When compared to the fates of some Chaos cultists, especially those who fail (think living flesh bag of pain and get worse), the bloodthirsty insanity and difficulty of speech is not that bad and the BodyHorror comparatively mild. Once transformed, you're likely to see your fate as CursedWithAwesome.
** The jungles of [[DeathWorld Catachan]] has a cactus-like plant called the Spiker which fires its spikes out at nearby animals. These spikes contain mutagenic chemicals that transform any animal unfortunate enough to be pierced into another Spiker.
* One of ''TabletopGame/FengShui'''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 ZombieApocalypse 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 ''TabletopGame/{{Cyberpunk}}'' sequel game, ''Cybergeneration''.

* The Exsurgent virus family in ''TableTopGame/EclipsePhase''. Different strains can infect computers...or flesh...and the result is never, ''ever'' pretty, usually featuring BodyHorror and ''always'' featuring MindRape. Oh, and they're very, very adaptive. Like, normal-viruses-on-crack adaptive. A digital strain can infect a [[MatterReplicator nanofabricator]], reprogramming it to produce [[BodyHorror biological]] and [[GreyGoo nanotechnological]] variants, which then go on to infect other beings and devices. Oh, and it can also be transmitted as pure sensory information, so you can get infected just by watching the [[BrownNote wrong video]], known as a basilisk hack.
-->"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."
* A third-party ''TabletopGame/{{Pathfinder}}'' supplement inverts this with the [[http://www.d20pfsrd.com/races/3rd-party-races/alluria-publishing/Obitu Obitu]] race, a race of living skeletons created by a virus that only infects the undead.

* ''TabletopGame/RocketAge'': Although it hasn't yet been used in a printed adventure, the game does provide [=GMs=] with the Infection trait, allowing them to make their own space zombies and vampires.
* ''TabletopGame/{{Shadowrun}}'': HMHVV (Human-Meta-Human-Vampiric-Virus), a supernatural disease that afflicts sapient primates -- meaning metahumans and sasquatches -- with lycanthropy and vampirism. There are three known strains, where strains II and III (the lycanthropic and ghoul variants) infect by any exchange of bodily fluids (i.e. being bitten or scratched) while strain I (the vampiric variant) only infects people completely drained of [[LifeEnergy Essence]]. ''Dark Terrors'' implies that HMHVV is actually a meta-sentient force. Further, if the Infected commit sustained cannibalism, [[spoiler:the virus concentrates to the point that it manifests ''eldritch gods'']].

* ''ComicBook/BeastWarsUprising:''
** The G-Virus, the last remains of Galvatron, which turns anyone it touches into a duplicate of the former Decepticon leader, winning personality and all. During ''Micro-Aggressions'', Grimlock has it stolen so he can try and turn the Builder higher-ups into immobile Galvatrons, ending the Uprising. Hot Rod tries to stop this on the grounds that it would also infect the still very mobile Micromasters, Maximals and Predacons nearby as well. [[spoiler:Unfortunately for everyone, a Micromaster was already infected during the Virus' theft, and while everyone's busy, turns into Galvatron and escapes into the night.]]
** In the finale, the Builders are pushed to desperation by the Resistance. [[spoiler:They unleash the Vehicons, who infect Cybertronians with a virus that removes their spark and turns them into more Vehicons. Within a few days of being unleashed, they manage to take 70% of the planet. Then it turns out they can infect Autobots and Decepticons too. It's all part of their creator's plan to remove the spark of every living thing on Cybertron.]]

* The old ''VideoGame/Area51'' lightgun game revolves around an alien virus being unleashed and causing a ZombieApocalypse in the area. The GameOver screen shows a video of the protagonist morphing into one of the alien mutants.

* ''[[VideoGame/BloonsTowerDefense Bloons TD 5]]'' has Viral Frost, one of the tower upgrades of the Ice Monkey. When Bloons are frozen by Ice Monkeys with this upgrade, other Bloons that touch these Bloons will also be frozen, as if the freezing effect is spreading like a virus, hence the name.

* The [[ZombieApocalypse zombie]] [[SurvivalHorror survival]] [[WideOpenSandbox sandbox]] ''VideoGame/TheDeadLinger'' takes place after a virus called HNZ turned the majority of people into zombies suffering from necrosis, reduced intelligence and a hunger for human flesh. The only good thing is that they become slower and eventually die off if they "live" long enough. The really bad thing: ''The player is not immune!''
* The ''VideoGame/DeadRising'' series has an example that isn't, strictly, a virus: ''[[https://deadrising.fandom.com/wiki/Ampulex_Compressa_Giganteus Ampulex Compressa Giganteus]]'' are genetically modified wasps created to address a food crisis, but mutated so that its parasitic breeding practices which originally only impacted butterflies affected humans, leading to infected humans becoming zombies.

* The A-Virus in ''VideoGame/{{Disgaea 4|A Promise Unforgotten}}'' is a humorous take on the trope, but nonetheless horrifying in its own way. [[spoiler:It transforms the infected into [[VideoGame/Disgaea2CursedMemories Axel]], in both body (Clothes included, somehow) and mind, Initial signs of infection include random bouts of [[HotBlooded hotbloodedness]], and/or referring to oneself as "ore-sama" ([[LostInTranslation Not to be retained in the English version for obvious reasons]]). Everyone gets better in the end, though. [[NonStandardGameOver Or not]].]]

* ''VideoGame/{{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 NonStandardGameOver where the player watches the transformation into a monster.

* Alma does this to Sergeant Keegan in ''VideoGame/FEAR2ProjectOrigin'', using her psychic powers to literally make him fall in love with her. The only way to save him is to kill him.

* ''VideoGame/FinalFantasyXIV: Endwalker'' has [[spoiler:the Blasphemies, EldritchAbomination[=s=] born from a particularly powerful entity's "song" that utilizes "Dynamis", the power of emotions, to warp mortals into monstrous personifications of despair. These creatures, in turn, cause others to fall into despair and transform into Blasphemies.]]

* The Flood in the ''Franchise/{{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. That's not even considering how the Flood will also spread itself via airborne spores produced from AlienKudzu and MeatMoss, or by directly attacking living creatures to intentionally infest their wounds with Flood biomass that spreads and infects the victim. When the Flood hijack enough bodies, they build a Gravemind; a giant, rhyming, MagnificentBastard HiveMind. To make it even worse, [[AssimilationPlot the minds and memories of every infectee are all assimilated]] into the Gravemind (it occasionally brags 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 BodyHorror and the assimilation and hacking of even spaceships, this NightmareFuel 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.
** ''Literature/TheForerunnerSaga'' reveals that they're actually [[spoiler:the malevolent remains of a highly-advanced species known only as "the Precursors", with those "remains" taking the form of a seemingly inert dust which contained DNA traces that would bind to any living creature it was exposed to and slowly mutate them and their descendants over the course of generations with increasing erratic and horrific bodily and behavioral patterns. During their conflict against the Forerunners, they literally crushed entire planets with Precursor technology and could corrupt [=AIs=] and Forerunners by breaking them through a form of argument known as a "logic plague".]]

* ''VideoGame/HomeworldCataclysm'':
** The Beast subversion entity 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; [[XanatosSpeedChess cue the Naggarok calling in all of its "children" to catch the ''Kuun-Lan'' from three sides]].

* ''VideoGame/TheLastOfUs'' has cordyceps, a real-world fungus that commonly infects insects, but has mutated to infect humans as well. Those infected with the mutated strain of cordyceps become zombie-like madmen who lash out at other people, with long-term infection causing progressively worsening BodyHorror as the fungus breaches the body of the infected. Bites are a common form of transmission, but people can also contract the fungus by breathing in the spores released from the corpses of the infected.
* ''VideoGame/Left4Dead'' with the infection. In most cases the virus will turn most people into unintelligent "runner" zombies who will psychotically attack any uninfected individual. BodyHorror 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 asymptomatic carriers, individuals who show no signs of the infection but can still spread it. [[spoiler:As it turns out, all eight [[PlayerCharacter Player Characters]] are carriers.]]

** Though it involves no physical changes aside from a possible palette swap, the [=Maverick/Sigma=] Virus from the ''VideoGame/MegaManX'' franchise otherwise qualifies. Around ''X2'', [[BigBad Sigma]] has become one with the virus, allowing him to get [[HijackedByGanon brought back between games for a reappearance]] and making virus victims extensions of Sigma's will to an extent.
** The Maverick Virus was made by [[spoiler:Wily himself, with his other creation [[TheLancer Zero]] used as the [[PatientZero Patient]] [[{{Pun}} Zero]]]]. Before the events of the X series, Sigma fought [[spoiler:Zero]] and the latter lost the virus, but Sigma got infected. This left Zero with some side effects in, like getting a power boost from the Sigma Virus and being [[spoiler:mostly]] impervious to reinfection.
*** The Sigma Virus is shown in ''X5'' to have two other varieties: the Colony Virus, planted onto the [[ColonyDrop falling space colony Eurasia]], and the [[spoiler:Zero Virus, a crossbreed of sorts between the Colony and Sigma viruses, that shows up as purple holograms of Zero in the CyberSpace. The fact that it can hurt Zero alludes to the possibility of Zero getting infected and becoming [[SuperpoweredEvilSide Awakened Zero]] if Eurasia is not destroyed, as well as implying that it might be based on the original, unmutated virus.]]
*** After the Maverick Virus, ''VideoGame/MegaManZX'' has [[spoiler:Model W gained the ability to manipulate the thoughts of humans and Reploids alike. This became important for Albert's EvilPlan.]]

** The "Zero Virus" in ''VideoGame/MegaManNetworkTransmission'', which is a newly spawned virus that began spreading after the events of ''VideoGame/MegaManBattleNetwork1'' and has been adversely aflicting [=NetNavis=] infected with it, and what's worse is that there is a vaccine dealer going around the cyberworld selling fake vaccines that is causing the user's [=NetNavis=] to turn against them and go on a rampage on the net. [[spoiler:A ''VideoGame/MegaManX''-savvy player can spot what is the cause of said virus.]]
* ''Videogame/MassEffect1'' includes the [[spoiler:Thorian, which is a plant-like entity that uses spores to mentally control people through pain]]. Also, there's [[spoiler:Sovereign, a Reaper which controls the minds of its victims through a process known as "indoctrination". People controlled by Sovereign can only be saved by killing them]]. Both cases also involve instances where people choose to [[DrivenToSuicide overcome the mind-control the only way they can]].
** To further fit this trope, unguided or faulty indoctrination seems to wake the desire to become a cyberzombie, leading the victims to jump onto the zombiefying devices. This may or may not be intended as a failsafe.

* ''VideoGame/{{Overlord}}'' has an example of the "turns the victim into a mindless shambling zombie" type. The interesting part is how it spreads: [[spoiler:tracing it to the source in Haven's Peak will reveal patient zero to be a Succubus Queen. [[RefugeInAudacity The plague's a staggeringly virulent STD]].]]

** The Werewolf gets an extra heart if they get a date on the night of a full moon, but will lose half a heart if they get rejected during a full moon. Anyone they date during a full moon becomes a werewolf as well, gaining the advantages and drawbacks of dating on a full moon on top of their normal monster powers.
** The Vampire turns everyone they date into a vampire, and those turned can subsequently turn others. At the end of the game, the original Vampire gets half a heart for every player that's been turned into a vampire.
** The Mummy works like the vampire by spreading their "curse" to players they date, except they ''steal'' half a heart from cursed players at the end of the game. However, [[DoWellButNotPerfect the curse is broken and the bonus is lost if the curse is spread to ALL the other players]].
** Anyone dated by the Zombie gets turned into a zombie after the next night, and they can infect others as well. If all the other players get infected by the end of the game, it triggers a ZombieApocalypse and [[InstantWinCondition the Zombie wins]] regardless of how many hearts they had.

** One of the glitch pokemon is [[http://bulbapedia.bulbagarden.net/wiki/Charizard_%27M Charizard 'M]]. 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.

** The BigBad [[spoiler:Elizabeth Greene]] 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 [[spoiler:at Penn Station]], she's more dangerous anyway. Alex can't get ''half'' the bodycount she does unless the player's doing it on purpose. [[spoiler:The viral Alex, anyway.]]
* The Sands of Time in the ''VideoGame/PrinceOfPersia'' trilogy work like this. Once released, they instantly turn everything they come in contact with into a crazed EnemyToAllLivingThings (living in this case being the few lucky souls who weren't instantly transformed). Somehow, when the Prince is exposed in the third game of the series, he manages to resist instant transformation, although he still gains a SuperpoweredEvilSide. The Corrupted, from the sequel, are an aversion-it's their own damnn fault they're {{Eldritch Abomination}}s now.
* The strange virus from ''Puzzlebox'' boosts a person's resilience to injury, inspires creativity and drives its hosts mad.
* The ''VideoGame/RType'' 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 MultipleEndings, 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). [[spoiler: The R-13A Cerberus ending in ''Delta'' has your ship fail to escape the Bydo dimension and become part of a Bydo Tree. This same ship is encountered in ''Final'' as an OptionalBoss. [[AndThenJohnWasAZombie This happens to you again]] in one ending in ''Final'', where you even fight against your own former allies. The thing is that ''you don't even realize you were infected by it''.]]

* In ''VideoGame/SlimeRancher'', when a slime [[note]]such as a Honey Slime[[/note]] eats the plort of a different species [[note]]such as a Hunter Slime[[/note]], it becomes a Largo Slime.[[note]]A Honey Hunter Largo, in the example case.[[/note]] The Largo slime can produce its original plort in addition to the plort of the species it hybridized with, as well as inherit their diet and [[TrademarkFavoriteFood favorite food]]. This can be [[ExploitedTrope taken advantage of]], since combining a rare slime species with a more common one provides easier access to its plorts [[note]]Hunter Slimes are rare and have a rare [[TrademarkFavoriteFood favorite food]], while Honey Slimes are easier to find, are equally valuable, and their favorite food is readily available and farmable. [[GoneHorriblyWrong Also, largo slimes made with Hunter traits start feral, so hope their stomachs aren't full and you have some chickens.]][[/note]]

* ''VideoGame/StarWarsKnightsOfTheOldRepublic'' has [[http://starwars.wikia.com/wiki/Rakghoul 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 TheRemnant.

* ''VideoGame/{{Silpheed}}'' has [[spoiler:an entire ship -- the ship that ''refueled you about ten seconds ago'', to boot --]] get taken over by an alien virus and turns into not only an enemy alien, but also ThatOneBoss.

* In ''Subterrain'', a mysterious "infection" has wiped out a colony on Mars, turning people into violent monsters and leaving only one known survivor: the game's protagonist, Dr. Albert West. Exploring the derelict colony space uncovers several {{Apocalyptic Log}}s that slowly piece together the backstory. A set of such logs in the final area reveal the origin of the infection: [[spoiler:it's a modification of the nanotechnology originally developed by Dr. West to treat his wife's Alzheimer's disease. A co-worker stole the tech to sell it, but their boss, Jeff Murray, became obsessed with using it to create a new race of Martians. Jeff used it to mutate both himself and Dr. West's wife Jennifer into horrible monstrosities that "psychically" control the horde]]. In the final confrontation with [[spoiler:the transformed Jennifer, she asks Albert to join her. He can accept the offer and become a sort of "father" to the Martians]].

* Appears in the ''VideoGame/WarCraft'' 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.
* In ''VideoGame/WorldOfWarcraft'', the [[EldritchAbomination Old Gods']] Curse of Flesh "corrupted" the creations of the Titans on Azeroth into fleshy beings like themselves. In other words, ''every'' human, dwarf, gnome, and trogg (and possibly a few other species too) is "infected" by The Virus!
* ''VideoGame/{{Warframe}}'': The Technocyte Plague was originally created as a weapon by the Orokin to fight the Sentients, but it quickly got out of hand. Not only it does not work against its intended enemy - the Sentients are immune to infection by the Plague - but it infects both living flesh and machinery, turning them into horrifying amalgamations of twisted flesh. Whenever the Infested show up, everyone [[GodzillaThreshold drops everything to fight them]]. The Tenno are fortunately also immune to infection. [[spoiler:This is because they are already Infested. Since the Sentients could control Orokin technology, the Orokin needed a non-technological solution. They infected people with carefully controlled cultures of it, granting them superhuman strength, endurance, and durability. These were the first warframes]].

* A meta example: Some games with multiplayer modes offer a [[CosmeticAward achievement]] that is "earned" by playing online with or against another player who already has it, starting from a very small initial group of "infected". E.g. "Six Degrees of Schafer" in ''VideoGame/BrutalLegend'' started off with just Creator/TimSchafer having it, while "Bubonic" from ''VideoGame/XCOMEnemyUnknown'' has the viral theme in its name.

* Beitus in ''Webcomic/{{Hackbent}}'' (aka [[spoiler:Lutark Lampri]]) is literally this, but a variation of it. He touched both [[spoiler:[[http://mspfanventures.com/?s=2810&p=515 Rodard]] and [[http://mspfanventures.com/?s=2810&p=242 Haeton]] in his disguise instead of in his real form, and at the moment, it isn't obvious they're infected. (The actual infection is shown later.) He uses way more hidden form of this trope, but after he erases his own disguise, it's become more clear to see, like when he infects Skaia]].
** What's also rather unique is that [[spoiler:Beitus is able to choose how the infected will behave. While Haeton's only line when infected is: 'Join us', Rodard became a DeadpanSnarker and a MinionWithAnFInEvil]].
* The revenants in ''Webcomic/GirlGenius''. 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 revenants are the ''exception''. Most people infected go about their lives normally... but completely obedient to the Slaver Wasp creator.
* The Dimension of Pain demons from ''Webcomic/SluggyFreelance'' possess a spear that can turn human beings (and ferrets, apparently) into demons, and they use it frequently during their [[DemonicInvaders 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 ([[WildMassGuessing 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 ''Webcomic/MSFHigh'' are a legion of {{Green Skinned Space Babe}}s who, when forced to fight, turn their attackers ([[OneGenderRace 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."

* In ''Webcomic/{{Superidol}}'' computer-generated IdolSinger Rei Rei is the memetic version of this, with billions doing everything they can to be her, until the whole world revolves around her.
%%* [[http://www.explosm.net/comics/1403/ This]] ''Webcomic/CyanideAndHappiness'' strip.
* ''Webcomic/ZombieWaffe'' has [[FunWithAcronyms LARS]] (Likasi Acute Rabies Syndrome) a new form of rabies which turns those infected into zombies.

** The Cyprus, and her daughter Venus, living plant matter that can reanimate corpses as zombie drones. In the MirrorUniverse, Unity and Venus combined to form the Great Unity, also known as the Biomass, a virulent strain that absorbed much of the population. Until it kicked alt!Unity out and decided it was going to be a ''selective'' all-devouring singulatity.
-->'''Dan/Biomass''': You'll all be outside ''begging'' to be assimilated!
* ''Webcomic/TheKingfisher'' 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.
* [[Creator/TetsuyaNomura Nomura Syndrome]] in ''Webcomic/ManlyGuysDoingManlyThings'' started as gene therapy to keep men looking young, but [[spoiler:Gackt]] modified it to spread and turn men into the Bishonen type of man. It's later noted that there are other viruses out there, one to turn boys into the rugged manly type (think AmericanKirbyIsHardcore in virus form) and another to turn people into [[WesternAnimation/MyLittlePonyFriendshipIsMagic My Little Ponies]]. Turns out the cure is [[spoiler:Canadian healthcare.]]
* The planet Nemesis in ''Webcomic/MetroidThirdDerivative''. Being the source of all Phazon, it spawns Phazon meteors which are thrown into space and affect other planets. Phazon in high doses is lethal to any living beings that comes into contact with the material, though slow exposure can increase tolerance, increase the probability of body mutations, and decrease the probability of death by Phazon.
* ''Webcomic/SweetHome2017'' has the monsterization Virus, which - unlike most of the examples on this page - doesn't have a single, general direction of mutation. Instead, those that are infected by it are mutated accordingly to their desires. For example, "[[TheBrute Muscle]]" who is all but outright implied to have been a fitness nut of sorts (or desperately craved for muscles but could never build them) constantly craved for strength resulting in his unique mutation.
** The virus spreads incredibly fast and by the times the symptoms kick in, it is usually too late. [[spoiler: Even ''the protagonist'' is infected by this Virus.]]
** The origins of the Virus itself are so enigmatic that even in-universe, characters are immersed in EpilepticTrees with theories ranging from GaiasVengeance to alien involvement.

[[folder:Web Original]]
* The "Weegee virus" meme. It involves Weegee turning people into clones of himself with his stare, resulting in him making a big army. And these clones also have a stare, making it a true virus.
* ''[[https://www.youtube.com/watch?v=WPb5Hg9-Egk 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.
* ''Literature/WhateleyUniverse'' examples: The Palm is a [[AIIsACrapshoot 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 BodyHorror and WombLevel.
* The Computer Virus from ''Roleplay/WeAreOurAvatars''. In the past, it's infected many of the robotic characters, and most likely counts as NightmareFuel.
* 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 ContractualGenreBlindness. HilarityEnsues.

%%* The mal from ''Literature/TheSickLand''

* This is how Walkenization works in [[http://monstermaster13.deviantart.com/gallery/44872715 Monstermaster13's]] Walken saga.

** [[http://www.scp-wiki.net/scp-299 SCP-299 ("Infectious Tree")]]. If any part of a SCP-299 (even a single cell) touches or is inserted into a plant or animal, it will change the plant or animal into another SCP-299. The total time required depends on how large the plant or animal is.
** A mind-only variant, [[http://www.scp-wiki.net/scp-571 SCP-571 ("Self-Propagating Infectious Pattern")]]: a BrownNote which causes its victims to make copies of it and show it to other people.
** [[http://www.scp-wiki.net/scp-610 SCP-610 ("The Flesh that Hates")]], a disease that mutates infected individuals in a Flood-like manner.
** [[http://scp-wiki.wikidot.com/scp-630 SCP-630 ("Black Glacier")]]. Touching the strange ice causes the victim to slowly transform into more of the ice.
** [[http://www.scp-wiki.net/scp-1120 SCP-1120 ("Freeze Tag")]]. After the touch of a SCP-1120 has [[TakenForGranite petrified a human being]], that human becomes a new SCP-1120.
** [[http://www.scp-wiki.net/scp-1361 SCP-1361 ("Animal By-Product")]]. If any living creature consumes SCP-1361, it will be converted into more SCP-1361 over a period of 4-6 hours.
** [[http://www.scp-wiki.net/scp-1536 SCP-1536 ("Doppelgängers")]]. Any living creature whose form is taken by SCP-1536 will become a new SCP-1536 after it dies.
** [[http://www.scp-wiki.net/scp-2009 SCP-2009 ("Thomas Hoang")]]. Anyone who breathes in SCP-2009-02 spores created by SCP-2009-01 will become an example of SCP-2009-01 in 8-9 days.
** [[http://www.scp-wiki.net/scp-2650 SCP-2650 ("Pediatric Pupaphobia")]]. SCP-2650-B is the body of a former ventriloquist and magician who is still alive despite having a wooden sphere in place of his brain. If he can get a preadolescent child (between the ages of 5 and 9) alone, he can change them so that they're like him and under his control.

* ''Website/TheFederalVampireAndZombieAgency'': Vampires, zombies and werewolves are caused by a variation of a virus from the family of rabies.

* The Phalanx from the early/mid-'90s X-Men cartoon.
* ''WesternAnimation/SkeletonWarriors'': Baron Dark could change anyone not "pure of heart" into a Skeleton Warrior.
* ''WesternAnimation/SuperRobotMonkeyTeamHyperforceGo'': The Skeleton King generates mooks with one.
* ''WesternAnimation/TheTick'': 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 ''[[Franchise/TheTwilightZone 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 ''WesternAnimation/ThePiratesOfDarkWater'', the eponymous Dark Water had the ability to kill people outright, or [[TheCorruption corrupt them]] into mutated minions or mindless slaves. In one of the more NightmareFuel-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 ''WesternAnimation/{{ReBoot}}'' 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 one episode of ''WesternAnimation/TheSecretShow'', Doctor Doctor creates a [[ZombieApocalypse zombie virus]] that instantly infects someone if they utter the words yes and no.
* In ''WesternAnimation/CodeLyoko'', 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, ZombieApocalypse-style.
* ''WesternAnimation/CodenameKidsNextDoor'': [[OurVampiresAreDifferent Count]] [[ComedicSpanking Spankulot's]] ability to turn other people [[spoiler:and stuffed animals]] into Spank-Happy Vampires. Instead of the traditional vampire bite, he spanks his victims without his gloves, and the only way this curse can be reversed is having the victim spank back the vampire who spanked him/her or spank the original vampire, Count Spankulot himself. No spanking, however, can be done unless the individual has broken a rule. This is demonstrated in the episode "[[Recap/CodenameKidsNextDoorS3E8BOperationLOCKDOWN Operation: L.O.C.K.D.O.W.N.]]", when he lures Numbuh One into his jail cell, then the latter goes on to spread his curse to the others during a {{Lockdown}} [[ExactlyWhatItSaysOnTheTin of the Treehouse]]. However, when this happens again in ''VideoGame/OperationVIDEOGAME'', it has the transformation be reversed with a few hits of a S.P.L.A.N.K.E.R.
* A robot from a planet of robots fears humans are The Virus in the ''WesternAnimation/{{Futurama}}'' episode, "Fear of a Bot Planet".
-->'''Robot:''' Is it true, humans sneak into your room at night, drain your fluids, and ''turn you into a human''?

-->'''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.
* Played for laughs in an episode of ''WesternAnimation/CampLazlo''. 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.
* ''WesternAnimation/Ben10AlienForce'':
** The Xenocites transforms carbon-based lifeforms into a [=DNAlien=] under the thrall of the [[ScaryDogmaticAliens Highbreed]]. [[spoiler:Thankfully, the Omnitrix has the power to revert the genetic damage and restore the original form of the victims.]]
** The [[NanoMachine nanite]] [[HiveMind hive]] from the Alien Swarm movie is another example.
* ''WesternAnimation/TheTransformers'' has the HatePlague 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 ''WesternAnimation/BeastMachines'', 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.
* An episode of ''WesternAnimation/SamuraiJack'', "The Aku Infection", dealt with Jack being infected by Aku's spirit, which began to [[BodyHorror transform Jack into Aku from within]]. Jack had to defeat Aku in a BattleInTheCenterOfTheMind to purge himself, drawing on his experiences and the good he's done in the future for power. [[ThePowerOfFriendship Aku never stood a chance]]. (The strangest part is, Aku never intended to do it to Jack; it occurred by accident when the villain simply sneezed on his foe during a battle, because he was sick with a terrible cold). [[spoiler:The only time he does this intentionally was en masse during the finale on a portion of Jack's allies]].
** However, Season 5 reveals that [[spoiler:beings like the High Priestess could drink a ''whole'' chalice of what Jack swallowed without suffering a horrific transformation due to being so morally depraved]].
* The Fudd from ''WesternAnimation/DuckDodgers'', a parody of the Flood which transformed people into goofy-looking Elmers with speech impediments.

* In the ''WesternAnimation/RickAndMorty'' season 6 premiere, Mr. Frundles turns anything it bites into another Mr. Frundles, which spreads very quickly until the Earth itself becomes a Mr. Frundles. Rick opts to move his family into another universe rather than bother trying to fix it.
* ''WesternAnimation/TheRealGhostbusters'' had an episode which culminated in a group of werewolves (who could turn bitten victims into werewolves) started fighting their enemies, a group of vampires (who could turn their bitten victims into vampires). As you might expect, the four heroes [[ScrewThisImOutOfHere decided to get the hell out of there and not look back]] before it got worse.
** One of the recurring villains of the show, the Grundel, was a green-skinned ghost that preyed on badly-behaved children. Any child who willingly accepted the Grundel's influence would slowly transform into a copy of it and in turn seek out other kids to infect.
* In a ''WesternAnimation/PhineasAndFerb'' Halloween Special titled "Night of the Living Pharmacists", Dr. Doofenshmirtz accidentally made one of these, with zombie-like copies of himself chanting "lots of me..." roaming all over Danville, turning anyone, including [[Film/ShaunOfTheDead cameos]], [[HalfHumanHybrid animals]], [[spoiler:and [[AnyoneCanDie the main characters]]]] into a zombie [[RunningGag pharmacist-looking guy]] with just a touch.
* A multi-episode arc of ''WesternAnimation/GuardiansOfTheGalaxy2015'' featured Peter Quill and company having to deal with a breakout of the "Venom" symbiotes from one planet, nearly infesting a highly populated one, and then overrunning Asgard, transforming all the Asgardians except Heimdall.
* "Hulked Out Heroes," an episode of ''WesternAnimation/AvengersAssemble'', features AIM creating a "gamma virus" that infects all of the Avengers except Black Widow and Hulk himself (who is obviously immune). The virus transforms the heroes into Hulking versions of themselves, and gradually makes them bigger, stronger, and more mentally unstable as time passes, with the eventual goal being total disintegration.

** Bacteriophages work the same way - being viruses that target bacteria.

** Filoviruses (Marburgvirus and the various Ebolaviruses) do the same thing. [[Main/NightmareFuel Only to humans, at the human level]]. Richard Preston's ''The Hot Zone'' provides ''very'' graphic descriptions of what these viruses do to their hosts. The scariest part is that it's '''non-fiction'''. Well, sort of nonfiction - the book provides a very well-written and graphic account of a man infected with Marburgvirus "crashing," but from there on becomes a very dry and rather misleading history of the Reston Ebolavirus outbreak (which is non-infectious in human beings), and makes some rather dramatic misrepresentations of EBOV's level of infectivity - EBOV is indeed very infectious, but also very difficult to transmit and generally requires fluid contact with an infected person who is symptomatic.
** 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 [[Film/TwentyEightDaysLater Rage]]. Fortunately it tends to kill within a week of showing symptoms, and although humans can (in theory) transmit it through a bite, the only confirmed human-to-human transmissions of rabies have so far [[https://www.nejm.org/doi/full/10.1056/NEJMoa043018 occurred]] [[https://wwwnc.cdc.gov/eid/article/23/9/16-1704_article through]] [[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC509042 organ]] [[https://aasldpubs.onlinelibrary.wiley.com/doi/10.1002/lt.20580 transplants]]. Fortunately as of 2021, the amount of people affected by these transplants number in the single digits.

** The worst part is that prions tend to be thermostable, so [[FirePurifies heating]] the infected flesh does ''NOT'' make it safe to eat. That's why mad cow disease is bad, bad news - not only do you have to cull the infected herd to prevent further infection, but the dead flesh remains hazardous.

** The ''VideoGame/MetroidPrimeTrilogy'''s Phazon is an example, but to very varying degrees, depending on the game and target. In ''VideoGame/MetroidPrime2'', the Ing also have a tendency to take over the bodies of other creatures, both living and [[ZombieApocalypse dead]].

* The Super Mutants from the ''VideoGame/{{Fallout}}'' games were created by the Forced Evolutionary 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 NonStandardGameOver.