History Main / ParasiticImmortality

* ''Website/SCPFoundation'': By using SCP-963, Doctor Bright can transfer his consciousness into a new host body with all his memories. However, [[DeathOfPersonality this replaces the host's brain waves with those of Dr. Bright]]. If SCP-963 is not removed in 30 days. it will cause the host to [[MesACrowd possess an exact duplicate of Dr. Bright's consciousness]].

* ''Literature/{{Leech}}'': [[spoiler:The titular leech]] is a hive mind that has existed for centuries by moving from human host to human host -- the plot involves it encountering a parasite even more vicious than itself.

* ''Literature/HeraldsOfValdemar'': Ma'ar, the Mage of Black Fire, attempted to cheat death during the Mage Wars set in the series past by possessing one of his progeny. Unfortunately for him, the spell was botched and his own personality was too dormant to take control of the host, merely subtly influencing them with his worst traits. Even worse, every time his soul transfers to a new host, the host and Ma'ar lose some of their magical ability, ultimately leaving the combined entity weaker. The final host was half-crazed from Ma'ar's influence, and barely powerful enough to be an apprentice mage.

The results of this type of immortality may be very detrimental to the host. Worse case usually leads to a DeathOfPersonality and a TransformationOfThePossessed of the victim, even the most mutualistic examples may still cause a SplitPersonalityMerge, a SplitPersonalityTeam, or SharingABody at best. However, Commensal types usually exist unnoticed by the host and don't affect them in any way. In some special cases, users may gain enough skill over the years to eventually even [[HijackingCthulhu Hijack Cthulhu]]. However, most of the time [[AchillesHeel the weakness of this Immortality]] is when someone [[KillTheHostBody kills the host]] before they can jump ship. If the parasitic character in question is an artificial intelligence, then their appropriation of a human body, machine, or body of an android, may induce a MindReformatDeath for the contained consciousness or intelligence.

SubTrope of {{Immortality}} and BodySurf, see also FamilialBodySnatcher for when the host is related. This trope more often than not crosses over with ImmortalityImmorality and ParasitesAreEvil due to its very nature. May result in somehow becoming TrappedInTheHost as a form of karma. Compare HeroicHost and SymbioticPossession. For examples in which the character drains the life or soul to live, see LifeDrinker and YourSoulIsMine.

* ''Anime/DragonBallZ'': Captain Ginyu's signature move [[GrandTheftMe allows him to swap his mind with that of his target]]. His ''modus operandi'' is to mortally wound his current body before replacing it with the one he desires, a strategy he uses first to claim Goku's body and then tries to repeat against Vegeta. He misses the second time, hitting a random frog and becoming trapped in its body for the remainder of his days [[spoiler:until he is killed in Tagoma's body during ''Anime/DragonBallSuper''.]]

* ''Manga/FateKaleidLinerPrismaIllya'': [[spoiler:This is how Darius has remained the head of the Ainzworth family.]] He uses Displacement magecraft to attach his soul to [[spoiler:the "next head of the family", and each time he does, something of his personality gets erased. It started with him losing a scar and forgetting an emotionally charged event connected with it, and now there's barely anything left of the original. This has been going on for ''millennia''.]]
* ''Manga/MagiLabyrinthOfMagic'': [[BigBad Arba]] has secretly manipulated the rise of the Kou Empire (the manga's equivalent of ancient China) to generate wars, distress, and chaos across the world. In order to keep an eye on the royal family, she created a spell to take over the bodies of certain members of the Imperial family, allowing her to keep so reincarnating in the bodies of its female members, overwriting their personalities. She does this with the current empress, Ren Gyokuen, [[spoiler:and after her death, she possesses Ren Hakuei, Gyokuen's daughter. Even when she's forcibly expelled from her body she tries to take over the body of her son Hakuryu.]]

* ''Film/BeingJohnMalkovich'': The twist behind the door that leads inside the mind of Creator/JohnMalkovich. [[spoiler:The door was discovered by Dr. Lester (AKA Captain Merton), who uses it to take over "vessel bodies" connected to it and live forever by jumping from body to body on each subject's 44th birthday. He ultimately succeeds in possessing Malkovich, and at the end plots to do the same to Malkovich's daughter eventually.]]
* ''Film/GetOut2017'': [[spoiler:[[{{Cult}} The Order of the Coagula]] have managed to achieve immortality through a procedure involving Hypnotizing black people, and then transplanting the brains of cult members into their bodies.]]
* ''Film/HorrorExpress'': [[BigBad The unnamed alien]] terrorizing the titular Orient Express train is revealed to be a formless EnergyBeing who can leap from lifeform to lifeform, and by the time of the film has already lived for millions of years at the very least. Should its current host be killed and the alien be unable to find a new body to inhabit, it will die, which is ultimately how the protagonists kill it during the ending, by derailing the train off of a cliff, with the alien still inside.

* ''Literature/TheMachineriesOfEmpire'': Hexarch [[ImmortalRuler Nirai Kujen]] exists as a VirtualGhost in the Black Cradle and needs a MeatPuppet to act outside it. Unlike the other occupant of the Cradle, he can BodySurf at will and control his host's actions with effort; however, he tends to let the host act on his behalf and at least one host enjoys his company.

* ''Series/StarTrekTheNextGeneration'': In "[[Recap/StarTrekTheNextGenerationS2E6TheSchizoidMan The Schizoid Man]]", Dr. Ira Graves effectively does this with Data. Somehow, he transfers his consciousness into Data's body and eventually emerges, replacing Data's mannerisms and personality. He realizes his own strength (from Data) and personality make him a poor fit to continue living, so he transfers himself out of Data's body, and into the Enterprise's computer, where the information of his mind is saved, but his human consciousness and awareness is lost.
* ''Series/StarTrekDeepSpaceNine'': The Trill can join with a symbiont species that retains their memories long beyond the Trill's natural lifespan, blending personalities with each successive host. Unlike most examples, the hosts seek this voluntarily and since there's only about 500 symbionts and millions of Trill there's much competition to qualify for one.
* ''Series/StarTrekVoyager'': In "[[Recap/StarTrekVoyagerS3E9Warlord Warlord]]", three individuals are rescued from their ruined and self-destructing ship, but Kes suddenly begins to show signs of abnormal personality. It turns out one of the individuals was a planetary dictator named Tieran who cheated death by finding a way to BodySurf to new individual bodies, replacing their consciousness. [[GrandTheftMe He absconds with Kes' body]], back to his original home planet, to reinstall himself as the ruler, but unfortunately for him, Kes isn't the InnocentFlowerGirl that everyone thought she was; she's fighting back with all her might, and it's taxing Tieran's consciousness. (Even extending a nap that he intended to have only for a few minutes, to 4 ''hours''. Although it's small, it's still a sign that something is seriously wrong for him.)
--> '''Kes:''' I'll find every little crack in your defenses. You'll feel yourself crumbling from within, your sanity slipping away. I won't stop until you're broken and helpless. There's nowhere you can go to get away from me. I'll be relentless, and merciless, ''just. like.'' '''''you!'''''

* ''TabletopGame/DungeonsAndDragons'': Unlike normal [[OurLichesAreDifferent liches]], {{Dracolich}}es can't reform from their SoulJar when destroyed. As a result, they need to [[PossessingADeadBody possess the nearby corpse]] of a dragon or reptilian creature.

* ''TabletopGame/Warhammer40K'': The Slaneeshi champion Lucius the Eternal wears armor covered in the screaming faces of his victims. If anyone ever manages to kill him (and feel any satisfaction at [[DidYouJustPunchOutCthulhu having killed a Champion of Chaos]]), their body slowly morphs into that of Lucius as he possesses them until the killer is just another face on Lucius' armor.

* ''VideoGame/DetroitBecomeHuman'': One of Connor's endings has him [[spoiler:transfer his memories into his [[EvilTwin pro-human version]] and thus [[TheNeedsOfTheMany save the Android Rebellion at the cost of Hank's life]].]]

* ''WesternAnimation/BatmanBeyond'': "Out of the Past" features the return of Ra's Al Ghul, who was thought to be long dead before the start of the series. After Ra's' body was mortally wounded to the point even the Lazarus Pit was unable to do anything for him, he decided to insert his consciousness into his daughter Talia's mind, which basically killed her and gave Ra's full control of her body. Ra's intends to do the same to Bruce, having come up with a plan to trick the latter into rejuvenating himself using the Lazarus Pit so that Ra's can steal his body and return to Gotham pretending to be the son of Bruce and Talia in order to get control of Bruce's assets. Bruce is so disgusted by Ra's' actions that he's willing to leave him for dead when Ra's' lair explodes and forbids Terry from trying to save him.
-->'''Bruce:''' Sure, Ra's, why not? Anything to hold off the Grim Reaper another few seconds. I take it back. You don't cheat death; you whimper in fear of it!
* ''WesternAnimation/TheOwlHouse'': [[spoiler:After being splattered by The Collector and going to the Human Realm, Belos possesses the local animals while he reconstitutes himself, though this quickly kills them and nearly does the same to Hunter. Upon returning to the Demon Realm without a host, he rapidly deteriorates until he can barely move, forcing him to possess a failed Grimwalker. Belos later takes over and impersonates a transformed Raine, with their puppet body being immune to decay]].

[[folder:Visual Novels]]
* ''Franchise/{{Nasuverse}}'':
** ''VisualNovel/FateStayNight'': [[EvilOldFolks Zouken Matou]] is the immortal patriarch of Matou family thanks to the use of his own personal magic that lets him transfer his consciousness into his worm-bugs, who in turn eat people in order to stay alive, living more like [[TheWormThatWalks a mass of critter shaped like a person]] than as a proper human. He is called a "vampire" by various characters [[note]]in a certain sense, they are right. In Nasuverse terms, a vampire is an [[InUniverse]] umbrella term used by the Church to cover all kinds of beings that extend their lifespans by draining the life from other living beings.[[/note]] and his mental state seems to deteriorate with each new change to stay alive because his "soul" is rotting.
** ''VisualNovel/{{Tsukihime}}'': This is how [[BigBad Roa Valdamong]] achieved immortality: while he was alive in his own body, he magically prepared a number of unrelated individuals across the world as future host bodies, so when his body died, he transferred his consciousness to one of the candidates and repeated the process, thus staying alive for hundreds of years. In the story proper, [[spoiler:Ciel]] is the most recent host whose body inexplicably came back to life after she was killed and Roa had already left it behind. [[spoiler:SHIKI Tohno, Akiha's ''real'' biological brother,]] is the current host, to whom Roa's spirit transferred after that.
[[/folder]]

* ''WebAnimation/{{RWBY}}'': [[BigGood Ozpin]] has been [[TheChosenOne tasked]] by the God of Light with redeeming humanity, requiring him to reincarnate in new hosts each time he dies; their souls, memories and personalities [[{{permafusion}} merge]] each time in a process neither can control. While Oz has learned how to share lives with his hosts intead of overwriting them, LossOfIdentity is normal for both and DeathOfPersonality is a risk for either one. Forced to fight [[BigBad Salem]] for [[ForeverWar millennia]], who is seeking to [[SuicidalCosmicTemperTantrum destroy humanity]], Oz has learned the hard way that her CompleteImmortality inflicts [[DespairEventHorizon such despair]] on those who fight her that he's become a secretive, manipulative {{Chessmaster}} to protect people's hope. Once TheParagon of his generation, the [[ItSucksToBeTheChosenOne toll of his existence]] has left him [[GuiltComplex riddled]] with guilt, regret and self-loathing.

->''"I once told you I made more mistakes than any man, woman, or child on this planet. I wasn't exaggerating. I'm... cursed. For thousands of years, I have walked the surface of Remnant; living, dying, and reincarnating in the body of a like-minded soul. The Professor Ozpin you all met was not my first form, and it clearly wasn't my last. It's... an extraordinarily strenuous process, on everyone involved."''

* ''WebAnimation/{{RWBY}}'': [[spoiler:Ozpin]] had been tasked by the Brother Gods to unite humanity by the time they return, lest they destroy all of Remnant as a failed experiment. To make this possible, they gave him the ability to constantly reincarnate into new hosts every time he dies, retaining all of his memories and merging his personality with each host whether they like it or not. This has allowed him to wage a secret war against Salem for thousands of years and [[BeenThereShapedHistory shape Remnant's history]] in his many incarnations, but it has also taken a massive toll on his mental state, turning him from a [[TheParagon virtuous paragon of heroism]] into a paranoid, shady and manipulative Chessmaster who feels immense guilt and regret at being forced to destroy the personalities of his hosts without being able to stop it from happening. [[spoiler:This is taken one step further when it's revealed that his immortality was likely made this way on ''purpose'' due to the existence of [[{{Reincarnation}} Ascension]], a process from the mythical Ever After that not only doesn't force hosts to house another personality but also erased the memories of the reincarnated so as to allow them to have a fresh start. This is presented as the ''proper'' way for this to happen, with strong implications that the God of Light made his variant parasitic in order to torment Ozma and Salem.]]

* ''WesternAnimation/SouthPark'': "[[Recap/SouthParkS4E14Pip Pip]]" has Miss Havisham trying to use her Genesis Machine to transplant her consciousness into her daughter Estella's body to prolong her life. Her plot is foiled when Pip convinces Estella she has a heart and gets her to leave the Genesis Machine while it's working. This causes the machine to explode, killing Miss Havisham.

* ''WesternAnimation/BatmanBeyond'': "Out of the Past" features the return of Ra's Al Ghul, who was thought to be long dead before the start of the series. After Ra's' body was mortally wounded to the point even the Lazarus Pit was unable to do anything for him, he decided to insert his consciousness into his daughter Talia's mind, which basically killed her and gave Ra's full control of her body. Ra's sets his mind on doing the same to Bruce, having come up with a plan to trick the latter into rejuvenating himself using the Lazarus Pit so that Ra's can steal his body and return to Gotham pretending to be the son of Bruce and Talia in order to get control of Bruce's assets. Bruce is so disgusted by Ra's' actions that he's willing to leave him for dead when Ra's' lair explodes and forbids Terry from trying to save him.

* ''WesternAnimation/SheRaAndThePrincessesOfPower'': Horde Prime is a mega {{Narcissist}} who creates the army of his clones. He also uses them to BodySurf to prolong his life. But this procedure is flawed: he must retain his old bodies to take access to memories from the time he occupied them because [[TheFogOfAges he forgot most of his past life]].

* ''VideoGame/DetroitBecomeHuman'': One of the endings for Connor is [[spoiler:for him to transfer his memory into his [[EvilTwin pro-human version]] and thus [[TheNeedsOfTheMany save the Android Rebellion at the cost of Hank's life]].]]

* ''VideoGame/{{Ico}}'': The BigBad is an evil queen who wishes to reclaim her youth by taking over her own daughter's body.
* ''VideoGame/ResidentEvilRevelations2'': The BigBad's research on immortality leads her to believe that the only way to escape death is by imprinting her consciousness into another host. By the end of the game, it's implied that she was successful in her goal, as one of the playable characters starts displaying some of her mannerisms.
* ''VideoGame/StarWarsTheOldRepublic'': In the Sith Inquisitor storyline, [[spoiler:Darth Zash turns out to aspire for this trope. The entirety of Act I involves the protagonist [[UnwittingPawn acquiring relics for her]] so she can possess you. Fortunately, your long-lost ancestor warns you before it happens]].

* ''[[Creator/HGWells The Story of the Late Mr. Elvesham]]'': A young man named Edward Eden meets an extremely old man named Egbert Elvesham who says he wants Eden to be his heir. When Eden agrees, Elvesham tricks him into taking a drug that transfers their minds into each other's bodies. Eden realizes that Elvesham has found a way to gain effective immortality as long as he can find new, young victims. Elvesham tricks Eden into taking a lethal poison, which ties up all the loose ends.

* ''Series/Babylon5'': "Exogenesis" introduces the Vindrizi, an ancient species of engineered symbionts that serve as living recorders, preserving knowledge while bonded to hosts who would otherwise have meaningless lives.

* ''Series/DoctorWho'': The Master pulled this off in the serial [[Recap/DoctorWhoS18E6TheKeeperOfTraken "The Keeper of Traken"]] where he possessed the body of a man called Tremas due to being out of regenerations. He did the same thing again in "[[Recap/DoctorWhoTVMTheTVMovie Doctor Who: The TV Movie]]" before finally getting a new set of regenerations during the Time War that happened between then and the show's 2005 revival.

* ''[[Creator/TaisTeng Dead Eyes]]''. An ancient Chinese emperor made a [[DealWithTheDevil deal]] with a demonic EvilSorcerer for eternal life. However, ordinary humans cannot be made immortal except by stealing the life force of others, so the sorcerer arranged for the emperor's soul to be placed into a new body whenever the current one died of old age. The plot is kicked off when the most recent transference goes wrong and causes the emperor to be trapped in a conscious host.

* ''Series/{{Babylon 5}}'': "Exogenesis" introduces the Vindrizi, an ancient species of engineered symbionts that serve as living recorders, preserving knowledge while bonded to hosts who would otherwise have meaningless lives.

* ''Series/DoctorWho'': The Master pulled this off in the serial [[Recap/DoctorWhoS18E6TheKeeperOfTraken "The Keeper of Traken"]] where he possessed the body of a man called Tremas due to being out of regenerations. He did the same thing again in [[Recap/DoctorWhoTVMTheTVMovie "Doctor Who: The TV Movie"]] before finally getting a new set of regenerations during the Time War that happened between then and the show's 2005 revival.

* ''Series/StarTrekTheNextGeneration'', "The Schizoid Man": Dr. Ira Graves effectively does this with Data. Somehow, he transfers his consciousness into Data's body and eventually emerges, replacing Data's mannerisms and personality. He realizes his own strength (from Data) and personality make him a poor fit to continue living, so he transfers himself out of Data's body, and into the Enterprise's computer, where the information of his mind is saved, but his human consciousness and awareness is lost.

* ''Series/StarTrekVoyager'', "[[Recap/StarTrekVoyagerS3E9Warlord Warlord]]": Three individuals are rescued from their ruined and self-destructing ship, but Kes suddenly begins to show signs of abnormal personality. It turns out one of the individuals was a planetary dictator named Tieran who cheated death by finding a way to BodySurf to new individual bodies, replacing their consciousness. [[GrandTheftMe He absconds with Kes' body]], back to his original home planet, to reinstall himself as the ruler, but unfortunately for him, Kes isn't the InnocentFlowerGirl that everyone thought she was; she's fighting back with all her might, and it's taxing Tieran's consciousness. (Even extending a nap that he intended to have only for a few minutes, to 4 ''hours''. Although it's small, it's still a sign that something is seriously wrong for him.)

* ''Series/StargateSG1'': The Goa'uld are worm-like parasites that can live for millennia, they also have sarcophagi that can prolong the lives of their human hosts a similar span but if they don't have access to one (like their DefectorFromDecadence faction the Tok'ra) they have to change hosts every couple centuries.

* In Creator/HGWells's 1896 short story "The Story of the Late Mr. Elvesham", a young man named Edward Eden meets an extremely old man named Egbert Elvesham who says he wants Eden to be his heir. When Eden agrees, Elvesham tricks him into taking a drug that transfers their minds into each other's bodies. Eden realizes that Elvesham has found a way to gain effective immortality as long as he can find new, young victims. Elvesham tricks Eden into taking a lethal poison, which ties up all the loose ends.

* ''Literature/TheHost2008'': The story revolves parasitic aliens called Souls who survive by taking other sentients as hosts. When the host dies, the Soul is removed and can be placed in a new host.

* ''Literature/HeraldsOfValdemar'': Ma'ar, the Mage of Black Fire, attempted to use this to escape his death during the Mage Wars set in the series past, body surfing into one of his progeny. Unfortunately for him, the spell was botched and his own personality was too dormant to take control of the host, merely subtly influencing them with his worst traits. Even worse, every time his soul transfers to a new host, the host and Ma'ar lose some of their magical ability, ultimately leaving the combined entity weaker. The final host was half-crazed from Ma'ar's influence, and barely powerful enough to be an apprentice mage.

** The Denarians are a group of {{Fallen Angel}}s who were sealed in [[ArtifactOfDoom silver coins]] and are unable to act unless the bearer of a coin becomes their WillingChanneler. Some hosts end up effectively trapped inside their own minds while the angel runs rampant, but others, like [[TheDreaded Nicodemus]], form a partnership with the angel and can share in their powers.

* ''Literature/TheHost2008'': The book parasitic aliens called souls who are placed in hosts (including humans). When the host dies, the soul is removed and can be placed in a new host.

* ''Film/XMenApocalypse'': Apocalypse was able to live for thousands of years by repeatedly transferring his essence into other mutants' bodies, a process which also allows him to [[PowerParasite steal those individuals' powers]]. Eventually achieving true immortality by taking over a man with a HealingFactor, Apocalypse is sealed away by rebels and spends 4000 years in a dormant state before being accidentally reawakened in 1983, after which he sets his sights on Charles Xavier, hoping to absorb his telepathic powers in order to exert influence across the entire globe.

* ''ComicBook/Transformers2019'': Exxarchon earned the "Threefold Spark" sobriquet because whatever mysterious "benefactors" drove him insane and unleashed him on Cybertron also granted him the ability to divide his [[OurSoulsAreDifferent Spark]] into three. This allowed him to control three bodies simultaneously, generally by infecting a Cybertronian and snuffing out their own Spark to replace it with his. A BadFuture shows him inhabiting the bodies of Megatron, Shockwave, and Onslaught, and through the story he takes over characters like Ruckus, Flatline, and Deathsaurus, taking over and abandoning bodies as he sees fit. His ultimate goal is discovered to be drilling to the center of Cybertron to infect the Allspark, the source of all Sparks, so he will achieve CompleteImmortality. It's also shown to be his greatest weakness: he has an instinctive need to control three bodies at all times, and the combined [[EnemyMine Autobot-Decepticon]] army take advantage of this to trap and destroy two-thirds of his Spark (and an Autobot assault team barely manage to destroy his final body before he locates the Allspark).

SubTrope of {{Immortality}} and BodySurf, see also FamilialBodySnatcher for when the host is related. This trope more often than not crosses over with ImmortalityImmorality due to its very nature. May result in somehow becoming TrappedInTheHost as a form of karma. Compare HeroicHost and SymbioticPossession. For examples in which the character drains the life or soul to live, see LifeDrinker and YourSoulIsMine.

SubTrope of Immortality and BodySurf, see also FamilialBodySnatcher for when the host is related. This trope more often than not crosses over with ImmortalityImmorality due to its very nature. May result in somehow becoming TrappedInTheHost as a form of karma. Compare HeroicHost and SymbioticPossession. For examples in which the character drains the life or soul to live, see LifeDrinker and YourSoulIsMine.