History Main / ParasiticHorror

Parasites are organisms which depend on feeding off living hosts for their survival. For sapient creatures such as humans, this is an inherently horrific concept as it violates all our ideas about bodily autonomy and how we interact with other creatures. While [[PredationIsNatural "normal" predation]] is at least intelligible to a species of former hunter-gatherers, parasitism seems to us both pestilential and insidious, not an acceptable part of the circle of life but some abberant perversion of nature.

SuperTrope to PuppeteerParasite, ChestBurster, ParasiteZombie, ParasitesAreEvil, and WombHorror.

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* ''Film/Venom2018'' is a {{subver|tedTrope}}sion of this. While Eddie is initially terrified by the Venom symbiote using his body as a host, and is especially horrified by his [[HorrorHunger new diet]] of [[BrainFood human brains]], Venom is actually sentient and able to be reasoned with -- and, as consolation, being his host also grants Eddie all kinds of cool superpowers. They grow to genuinely like and trust one another, to the point where Venom is hurt and angered by being called a parasite, insisting their relationship is mutually beneficial. By the end, Eddie's grown to like having Venom around, and offers the compromise that they only eat [[PayEvilUntoEvil bad people]], to which Venom agrees, allowing them to become a full-on HorrifyingHero.

* ''WebAnimation/DontWalkHomeAloneAfterDark'': The titular being in ''The Worm'' is a psychic parasite; it can latch itself onto the psyche of anyone who knows it exists and torments them in their dreams, feeding off their fear and other negative emotions. It can be spread from person-to-person by having someone already infected [[spoiler:tell someone else about it]].

* VideoGame/ScapeAndRunParasites is a GameMod that turns VideoGame/{{Minecraft}} into this, and has updated to the point where practically every mob in the Overworld could be warped into an [[BodyHorror unrecognizable monster]]. Even the [[FinalBoss Ender Dragon]] and the player aren't safe from the Call of the Hive as it gradually spreads across the world.

[[folder:Web Original]]

* VideoGame/ScapeAndRunParasites is a GameMod that is all about this, and has updated to the point where practically every mob in the Overworld could be warped into an [[BodyHorror unrecognizable monster]]. Even the [[FinalBoss Ender Dragon]] and the player aren't safe from the Call of the Hive.

* Deep Root Disease from ''WebVideo/GeminiHomeEntertainment'' involves an alien "plant" growing on human hosts, spread by insectoid creatures called "Woodcrawlers." As it grows, it converts humans into "fake people," who are agressive and territorial. It eventually reduces them to a tangle of red fibres in the vague shape of a person who CanOnlyMoveTheEyes. This phase is actually a carniverous plant called "Nature's Mockery."

*** One of his daemonic gifts is a BeneficialDisease in the form of a huge parasite that makes whatever vehicle it infests ''more healthy.''

* Deep Root Disease from ''WebVideo/GeminiHomeEntertainment'' involves an alien "plant" growing on human hosts, spread by insectoid creatures called "Woodcrawlers." As it grows, it converts humans into "fake people," who are agressive and territorial. It eventually reduces them to a tangle of red fibres in the vague shape of a person who CanOnlyMoveTheirEyes. This phase is actually a carniverous plant called "Nature's Mockery."

* Deep Root Disease from ''WebVideo/GenesisHomeEntertainment'' involves an alien "plant" growing on human hosts. As it grows, it converts them into "fake people," who are agressive and territorial. It eventually reduces them to a tangle of red fibres in the vague shape of a person who CanOnlyMoveTheirEyes.

* In ''TabletopGame/Warhammer40000'':

** [[PuppeteerParasite Mind-control worms]] are available as wargear.

** Slaan come in two varieties (red and blue), which are basically their sexes. They each lay eggs in an opponent on a successful unarmed melee touch attack, which need to be fertilized by the other color of slaan to take. In certain editions/settings, blue slaan eggs hatch into red slaan, and red slaan eggs hatch into blue slaan.

** In ''VideoGame/CastlevaniaSymphonyOfTheNight,'' Beelzebub makes an appearance as a huge zombie goat-man subjected to UnwillingSuspension. He attacks by dripping maggots on Alucard.

* ''Film/{{Growth}}'' is about an island that unwittingly hosts a secret government laboratory studying parasites. While they're intended to produce extremely big, shiny pearls, this is only a proof-of-concept. They are accidentally released, first infesting a creepy kid (who, does, as a matter of fact, have them swarming out of her eyes), then overrunning the whole island. The CruelTwistEnding of the film shows that [[spoiler: those pearls are actually their eggs, and they're hatching]]...

* ''Film/Venom2018'' is a {{subver|tedTrope}}sion of this. While Eddie is initially terrified by the Venom symbiote using his body as a host, and is especially horrified by his [[HorrorHunger new diet]] for [[BrainFood human brains]], Venom is actually sentient and able to be reasoned with -- and, as consolation, being his host also grants Eddie all kinds of cool superpowers. They grow to genuinely like and trust one another, to the point where Venom is hurt and angered by being called a parasite, insisting their relationship is mutually beneficial. By the end, Eddie's grown to like having Venom around, and offers the compromise that they only eat [[PayEvilUntoEvil bad people]], to which Venom agrees, allowing them to become a full-on HorrifyingHero.

* ''Fanfic/AbraxasHrodvitnon'': In this Franchise/MonsterVerse fanfiction, two of Ghidorah's "children" cause this. When the Many are being injected into their first human victims, it looks like something is slithering under the body's skin. One of the unborn [[spoiler:Zmeyevich]] kicking like a regular baby against its mother's belly is just a little bit more visible than is human.

* ''Film/{{Growth}}'' is about an island that unwittingly hosts a secret government laboratory studying parasites. While they're intended to produce extremely big, shiny pearls, this is only a proof-of-concept. They are accidentally released, first infesting a creepy kid (who, does, as a matter of fact, have them swarming out of her eyes), then overrunning the whole island. The CruelTwistEnding of the film shows that [[spoiler: those pearls are actually their eggs, and they're hatching...]]

* ''Film/{{Sputnik}}''. The alien lives in the host's oesophagus and stomach, and secretes a toxin that knocks out the host and relaxes his muscles so the alien can [[OrificeEvacuation exit via the mouth]] to hunt and feed, which it does every night. Once outside the body and ingesting oxygen it grows from a snakelike form to a multi-limbed Starfish Alien 1.5 metres in length. It's speculated that the alien is using the host as a spacesuit until it becomes fully adapted to Earth's environment, whereupon it will discard the host like a cocoon (turns out the relationship is [[TheSymbiote symbiotic]]).

* ''Film/Venom2018'' is a {{reconstruction}} of this. While Eddie is initially terrified by the Venom symbiote using his body as a host, and is especially horrified by his [[HorrorHunger new]] [[BrainFood diet]], Venom is actually sentient and able to be reasoned with--and, as consolation, being his host also grants Eddie all kinds of cool superpowers. They grow to genuinely like and trust one another, to the point where Venom is hurt and angered by being called a parasite, insisting their relationship is mutually beneficial. By the end, Eddie's grown to like having Venom around, and offers the compromise that they only eat [[PayEvilUntoEvil bad people]], to which Venom agrees, allowing them to become a full-on HorrifyingHero.

* ''Literature/ALittleVice'': [[spoiler:the seeds that empower the Beasts are this, and push the hosts towards their desired behaviour.]]

* ''Literature/ThingsHaveGottenWorseSinceWeLastSpoke'': The last parts of the book involve Agnes being convinced by Zoe to [[spoiler:[[NauseaFuel consume raw insect-infested meat]], willingly giving herself a tapeworm in order to fulfill her desire to be a mother.]]

* In one episode of ''Series/{{Primeval}}'' a flock of dodos manages to escape into a building in the present day. The dodos themselves are about as dangerous as you might expect, but they bring with them a highly infectious worm-like parasitoid that can also transfer to humans.

** In ''Series/StarTrekTheNextGeneration'', the episode "Conspiracy" plays the parasites for various types of horror: firstly, they [[PuppeteerParasite change people's personalities]], secondly, they make people violent and [[SuperStrength super strong]], thirdly they themselves look pretty gross with their appendages sticking out of the person's neck, and fourthly, some of them breed in somebody's stomach, causing him to explode.

[[folder: Tabletop Games]]

** Illithids (AKA, Mind Flayers) are parasitoidic, meaning their young can only (properly) mature inside a living host (when they don't, the result is a Neothilid), and kill them when they "hatch." In this case, the larvae eat their hosts brains over the course of around a week, and replace everything south of the nose with tentacles. It gets more complicated when different races get involved, but the basic concept remains the same.

* ''TabletopGame/{{Pathfinder}}:
** Boregrubs are parasitic worms that infest rotten wood and leap out when they sense suitable hosts (ie, player-characters). Boregrub-infested doors are a common booby-trap in HauntedHouse-themed dungeons.
** A certain Literature/CthulhuMythos-themed module has Dark Young of Shub-Niggurath born this way. They provide the host with immunity to mind-control for a couple of days before exploding out of their heads in a welter of gore and tentacles.

* VideoGame/CastleVania:
** In '''VideoGame/CastleVaniaSymphonyOfTheNight,'' Beelzebub makes an appearance as a huge zombie goat-man subjected to UnwillingSuspension. He attacks by dripping maggots on Alucard.
** ''VideoGame/CastleVaniaLamentOfInnocence'' has its first and bonus bosses be examples. The first boss is a huge, disembodied brain infected with an equally-huge brainworm. The bonus boss, the Forgotten One, is a BigRedDevil chained up in the basement who also attacks by spawning gigantic maggots from holes in its flesh.

* ''VideoGame/ResidentEvil4'' and ''VideoGame/ResidentEvil5'' involves a mutative PuppeteerParasite known as ''Las Plagas.'' They often reveal themselves as carnivorous arthropods growing on people's spines after their host gets decapitated.
* In ''VideoGame/SkiesOfArcadia,'' when the crew reaches TheEmpire, a certain enemy is a homeless man being piloted by a gigantic cockroach-like insect.
* ''VideoGame/SidMeiersAlphaCentauri'': Mindworms. Just Mindworms. The dominant native lifeform of Planet, Mindworms are small, maggot-like creatures that attack in [[ZergRush massive swarms]] and paralyze their prey with [[MindRape psychic terror]] before [[FaceFullOfAlienWingWong laying their eggs inside]] the brains of their [[AndIMustScream conscious, screaming victims.]] And they always make a beeline towards the biggest [[GaiasVengeance sources of pollution.]] [[SarcasmMode Fun.]]
* In ''VideoGame/SplatterHouse 3,'' the player-character's wife is infested with demonic {{Puppeteer Parasite}}s called "Boreworms." [[TimedMission You only have so much time to literally beat them out of her before they eat her brains and she dies of them]].
* ''VideoGame/StarCraft'''s Infested Terrans are stuffed so full of alien parasites they (both the poor space marine and all his new passengers) are bursting out of their spacesuits.

** Illithids (AKA, Mind Flayers) are parasitoidic, meaning their young can only mature inside a living host, and kill them when they "hatch." In this case, the larvae eat their hosts brains over the course of around a week, and replace everything south of the nose with tentacles.
** Slaan come in two varieties (red and blue), which are basically their sexes. They each lay eggs in an opponent on a successful unarmed melee touch attack, which need to be fertilized by the other color of slaan to take.

* In ''VideoGame/SplatterHouse 3,'' the player-character's wife is infested with demonic [[Puppeteer Parasite]]s called "Boreworms." [[TimedMission You only have so much time to literally beat them out of her before they eat her brains and she dies of them]].

* ''TabletopGame/{{Pathfinder}}: ** Boregrubs are parasitic worms that infest rotten wood and leap out when they sense suitable hosts (ie, player-characters). Boregrub-infested doors are a common booby-trap in HauntedHouse-themed dungeons.
** A certain CthulhuMythos-themed module has Dark Young of Shub-Niggurath born this way. They provide the host with immunity to mind-control for a couple of days before exploding out of their heads in a welter of gore and tentacles.

-->-- ''Lady Deirdre Skye, "Our Secret War"'', ''VideoGame/SidMeiersAlphaCentauri''

* A certain CreepyPasta involves a man on a bet to lose weight take anabolic steroids and a tapeworm pill together. The tapeworm begomes [[BigCreepyCrawlies giant]] and eats all his organs.
* ''WebOriginal/{{Mortasheen}}'', a horror-themed {{Mons}} world heavily influenced by real-life biology, has too many parasite-based monsters to list individually. Wormbrains are PuppeteerParasite flatworms that control genetically-engineered host bodies. Botanical monsters are cultivated as parasites of natural plants. The Genetimorph and Underfiend are dangerous parasitoid creatures whose offspring are {{Chest Burster}}s, whereas the Wrigglegeist is an endoparasite that lives harmlessly inside an unwary host. Still more Mortasheen parasites feed off of weirder things like genetic material and neural activity.

''"As the writhing, teeming mass of mindworms swarmed over the outer perimeter, we saw the defenders recoil in horror. 'Stay calm! Use your flame guns!' shouted the commander, but to no avail. It is well known that the Mind Worm Boil uses psychic terror to paralyze its prey, and then carefully implants ravenous larvae into the brains of its still-conscious victims. Even with the best weapons, only the most disciplined troops can resist this horrific attack."''
— ''Lady Deirdre Skye, "Our Secret War"'', ''VideoGame/SidMeiersAlphaCentauri''

* ''Film/{{Growth}}'', which provides the page image, is about an island that unwittingly hosts a secret government laboratory studying parasites. While they're intended to produce extremely big, shiny pearls, this is only a proof-of-concept. They are accidentally released, first infesting a creepy kid (who, does, as a matter of fact, have them swarming out of her eyes), then overrunning the whole island. The CruelTwistEnding of the film shows that [[spoiler: those pearls are actually their eggs, and they're hatching...]]

* The plot of ''VideoGame/BaldursGateIII'' concerns the protagonists being implanted with [[FaceFullOfAlienWingWong illithid tadpoles]], [[FindTheCure seeking a cure]] before the parasite eventually consumes their brains and transforms their bodies into [[{{Cthulhumanoid}} mind flayers]]. The opening cutscene demonstrates the implantation of these tadpoles, showing them entering their victim's skulls by [[EyeScream crawling around their eyeballs]] in a manner similar to the page image above.

* ''VideoGame/ResidentEvil4'' and ''VideoGame/ResidentEvil5'' involves a mutative PuppeteerParasite known as ''Las Plagas.'' They often reveal themselves as carnivorous worms growing on people's spines after their host gets decapitated.