Terminal Transformation

In fiction, literal transformations can have serious drawbacks, many of them functioning as Drama Preserving Handicaps to prevent more powerful or versatile shapeshifters from undermining the story. Depending on the kind of transformee, the process can result in anything from being stuck in one form or simply being unable to control the transition... or, in extreme cases, the transformation can be deadly.

The causes of such a lethal transformation are many and varied: in the case of full-time shapeshifters, it may be the result of a Superpower Meltdown or Power Degeneration; in the case of one-off transformations, it can be due to the source of the change being Toxic Phlebotinum; in some instances, it might even be the results of a weapon or sabotage. Regardless, the transformed character dies as a result of their transformation — often quite painfully.

Please note that the cause of death has to be the transformation itself, not a problem caused by the circumstances that follow. For example, being turned into a fish out of water — or a human deep in the ocean — would count under the rules of the trope. But if a character transforms into a mouse and ends up being stepped on (accidentally or otherwise), then it doesn't count; if a villain goes One-Winged Angel and is slain by the hero, it doesn't count.

Transformations that induce a Death of Personality can also fall under the heading of this trope, but only if the work definitely confirms that there's no way of restoring the victim to normality and their personality is definitely gone forever — no remnants, no hints of leftovers, gone. In other words, they need to be treated as dead by the story and characters, and there needs to be an actual transformation: zombies and vampires do not count under this heading, in part because the transition from human to undead usually involves them undergoing some form of death anyway.

A Super-Trope of Death by De-aging and Rapid Aging, and often an example of Transformation Horror. If this grants the receiver a temporary power boost before killing them, then it also counts as a Deadly Upgrade. Examples of irreversible petrification may fall under this heading if treated as death by the story.

Compare Shapeshifter Swan Song, when a shapeshifter changes through multiple forms at once before dying. Compare and contrast This Was His True Form for when a shapeshifter turns back into their original form as they die. See also Painful Transformation, when the transformation isn't necessarily fatal, but can certainly feel like it will be.

Contrast We Can Rebuild Him and Emergency Transformation, for when a dead person (or someone on the brink of death) is resurrected or healed by being transformed into something else.

As this is a Death Trope, unmarked spoilers abound ahead. Beware.

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Examples:

Anime & Manga

• Discussed in The 100 Girlfriends Who Really, Really, Really, Really, Really Love You. While Kusuri's Magic Antidote can reverse most of her drugs' effects, the baby transformation drug would kill the user if neutralized within an hour, and the body shrinking drug would kill the user if neutralized before it wears off.
• JoJo's Bizarre Adventure:
  • Stone Ocean: As part of his Evil Plan, Pucci engineers the creations of The Green Baby by having dozens of prisoners transformed into flora to absorb their souls.
  • Steel Ball Run: Sugar Mountain's Stand causes victims who accepts her Honest Axe are given a time limit to use all the items that were given before sunset otherwise they will be turned into branches that will immediately kill them.
  • JoJolion: The Higashikata Family has a Hereditary Curse that takes the form of an illness that affects the first born of every generation, slowly turning their body to stone. The only way to treat it is to exchange the curse with someone else, a role assigned to the child's mother, resulting in death.

Comic Books

• Cable: As a baby, Nathan Summers was infected with a techno-organic virus that slowly started turning his body into metal. He manages to keep the infection in check through his mental abilities, but if it ever finishes, he will die.
• The Spectre: The 70s run had the Spectre inflicting this on murderers as a means of getting past the comics code. These included melting a guy into a still screaming blob, turning another into glass that shattered, and transforming a crooked businessman into a cactus. It's safe to say that qualifies as murder, which is why the Spectre isn't really liked by other heroes.
• Ruins:
  • In keeping with the nature of the setting, Raven Darkholme is suffering from a Shapeshifter Identity Crisis that she has to be medicated for. Unfortunately, she fails to take her meds while she's on a plane with Philip Sheldon and loses control, ultimately suffering an extremely messy Superpower Meltdown. She's dragged away before we can see the results in their entirety, but Sheldon is told that her brain imploded; for good measure, the empty seat where she was sitting is soaked in blood.
  • In this version of Marvel canon, the space voyage that created the Fantastic Four went horribly wrong, apparently due to the ship being piloted by Victor Von Doom instead of Ben Grimm. As a result, the transformations that the characters undergo were undermined by a lack of Required Secondary Powers and resulted in the deaths of all four: Reed Richards' elastic powers made his bones stretch until they burst out of his flesh; Doom's internal organs ended up on the outside of his body; Johnny Storm's ability to become living fire caused him to burn to charcoal from the inside out. The one exception to this is Sue Storm, who survived her transformation — but as her invisibility left her blind, she stumbled into Johnny and was fatally burned.
• Transformers: More than Meets the Eye: The villain Sunder had the ability to convince his victims that the best way to fight him was to transform while simultaneously make them forget how to do so, resulting in them turning into an inside-out ball of parts. Fortunately for the crew of the Lost Light, Ratchet was a skilled-enough surgeon that he could reverse the transformation before it became fatal.

Fan Works

• In Eleutherophobia: Ghost in the Shell, after Margaret White is found guilty of murdering the voluntary hosts, she commits suicide by morphing into a fish in the courtroom. By the time someone brings her water, she's already dead. Not that it would have helped since she morphed into a salt water fish.
• Rarity of Equestria Divided suffers from a disease that is slowly turning her into an inanimate crystal statue; it's mentioned she suffers internal bleeding due to the crystalised parts cutting her fleshy ones when she moves, and that the final stage of this transformation will definitely kill her — either due to internal injuries or simply due to losing her mind to the transmutation.
• Harry Potter And The Invincible Technomage: Peter Pettigrew is badly injured and taken to a muggle hospital, undergoing numerous operations requiring his bones to be held together with steel screws. Once he's conscious again, he gets antsy about getting caught now that he's in human form and quickly shapeshifts into his rat form in order to escape... only to find too late that the steel screws in his body do not transform with him, resulting in an extremely painful death.
• The Land of What Might-Have-Been:
  • The Amorphous League induct new members via a ritual welcoming that ends with the prospective member taking their first dose of the shapeshifting potion, after which they experience a random bout of transformations. However, it's possible to get stuck in one form in this first shapeshifting session, and recruits who can't — or won't — work up the willingness to change again will die once the potion wears off and their body starts changing back of its own accord. Glinda briefly ends up stuck in this state when she joins the League, being trapped in Elphaba's form, and it takes a pep-talk from the real Elphaba to help her complete her metamorphosis.
  • Overdosing on the League's potion causes the victim to experience the much-sought-after state of Shapelessness, but without the ability to control it, eventually causing them to melt down into inert liquid. Worse still, the lack of sensory stimuli will eventually cause the unfortunate victim to lose all sense of self, leaving them effectively brain-dead. This is weaponized against the Empress to overwhelm her Healing Factor, rendering her into a liquid that can be kept in a pressurized can until her mind goes bye-bye.

Films — Animation

• Aladdin and the King of Thieves: The villain Sa'Luk suffers a Death by Irony when he grabs the MacGuffin, the Hand of Midas, by the business end. He has just enough time to realize his mistake before it transforms him into a lifeless gold statue.
• Atlantis: The Lost Empire: In the final fight to save Princess Kida, Milo cuts the crazed Commander Rourke with a piece of glass infected with the Heart of Atlantis's energies. Rourke's wound crystallizes and spreads through his body, transforming him into a monstrous crystal statue. He's still moving to attack Milo, but his crystallized form is visibly cracking open and explodes when he makes contact with his balloon's propellers, implying the transformation would've destroyed him regardless. And it couldn't have happened to a nicer guy.
• At the end of Rudolphand Frostys Christmasin July, the evil wizard Winterbolt turns into a tree after his scepter is destroyed, implying that the scepter in question was actually keeping him alive.
• Help! I'm a Fish: Near the end of the movie, Fly tricks Joe into drinking more of the potion by asking him questions, causing him to become smarter and more human-like... until he loses his gills and drowns.
• Shrek 2: In the finale, the Fairy Godmother attempts to kill Shrek once and for all, only for King Harold to throw himself in the way of her spell, his polished armour immediately deflecting it back on her. The Fairy Godmother is almost immediately reduced to a mass of bubbles and water — her wand and smashed glasses being the only part of her left unchanged. Since she's never seen in any of the sequels, it can be assumed that the transformation killed her.
• In Superman/Shazam!: The Return of Black Adam, Black Adam has been in supermode for thousands of years as he returns to Earth from deep space where he was banished. This means that his original mortal form Teth-Adam is long, long dead. So, when Captain Marvel threatens to send him even farther into space, Adam commits suicide by transforming back into Teth-Adam: the desiccated corpse quickly breaks down into dust and blows away.

Films — Live-Action

• Towards the end of Altered States, Eddie Jessup's evolutionary drug experiments cause him to dramatically transform and regress into a blob of primordial matter — and from there, a single-celled organism. By the time Emily is able to reach him, he's on the verge of ceasing to exist altogether, though she's able to guide him back to reality before it's too late.
• Beauty and the Beast (2017): In a Darker and Edgier take from the original animated film, it's revealed that the Enchantress's curse now operates under this rule. The spell still transforms all of the Beast's household staff into talking furniture and knickknacks, but in the original, failing to break the curse before the last rose petal fell would leave them stuck as walking, talking household items forever. Here, the spell makes the castle's inhabitants more thing-like as time goes by, and it's stated that if time runs out, they'll be permanently and fatally transformed into non-sentient objects. This ends up happening in the finale, but the Enchantress ultimately decides to bend her own rules to reverse the hex anyway, as she realizes that Belle did love the Beast even though she didn't explicitly say so until the rose withered.
• At the climax of The Gamers: Hands of Fate, Cass wins the Final Battle by bringing his opponent's entire undead army Back from the Dead as ordinary mortals... only for them to immediately starve to death, as none of them have eaten anything in days, because Cass's opponents previously destroyed all food production in their conquered territory to ensure nobody else could control it — on the assumption that the undead army wouldn't need food.
• Marvel Cinematic Universe:
  • Ant-Man:
    • Darren Cross's first attempts to replicate Hank Pym's shrinking technology are so imperfect they result in the test subject being reduced to a shrunken pile of goop. However, while trying to perfect the shrinking process, he also weaponizes the faulty tech to murder a troublesome co-worker... then mops up the victim's remains with a tissue and flushes the mess down the toilet.
    • In the finale, Cross dons the Yellowjacket suit for a sizeshifting battle with Scott, leaving the new Ant-Man on the backfoot for a good chunk of the fight. However, when Cross opens fire on Scott's daughter, Scott goes subatomic so he can sabotage the suit from within, resulting in different parts of Cross's body shrinking at once — crumpling him up like a ball of paper. This is retroactively subverted in Ant-Man and the Wasp: Quantumania, where it's revealed that Cross had barely survived the horrific transformation... with his head being disproportionately large and the rest of his body becoming a tiny appendage that couldn't support him anymore. He would have died in this helpless form had Kang the Conqueror not found and rebuilt him as M.O.D.O.K. (Mechanized Organism Designed Only for Killing).
  • Thor: Love and Thunder: Through Mjölnir, Jane Foster is able to transform her cancer-stricken body into that of a healthy, buff goddess known as Mighty Thor, able to fight monsters and other godly beings. However, the power of Thor saps her energy needed to fight off the cancer, which accelerates the disease spreading in her body. She is forbidden by Thor to partake in the Final Battle against Gorr out of fear that it would be the one that ultimately does her in, but Jane refuses to sit quietly when others need help. She takes up Mjölnir to become Mighty Thor one last time and fights Gorr head on before succumbing to the cancer.
• Super Mario Bros. (1993): President Koopa's Devo Gun can devolve a sentient being into a more primitive stage of its evolutionary history (from a human to a chimp for example). During the climax, though, President Koopa gets blasted with the Devo Gun, at first devolving him into a T-Rex and seemingly making him an even bigger threat... up until Mario and Luigi blast Koopa with two Devo Guns at full power, causing him to melt into green slime that splatters across the street, effectively killing him.
• X-Men: Magneto's big plan is to use a machine to transform all the diplomats at the UN summit into mutants, ending the conflict between Homo Sapiens and Homo Superior by converting the leaders of the former. He uses Senator Kelly as an unwilling guinea pig, enjoying the irony of turning the foremost anti-mutant opponent into something he hates. Unfortunately, the process is too unstable: though it successfully transforms Kelly into a Rubber Man, he soon begins to sicken, to the point that he barely makes it to the X-mansion before collapsing; soon after, Kelly's mutation causes his body to fatally dissolve into a mass of water.

Literature

• In the anthology book Alternate Kennedys, the short story "Told You So" focuses on John F. Kennedy gaining Reality Warper powers from a leprechaun. Unfortunately, this has ramifications for him when he says his famous "Ich Bin Ein Berliner" speech, the key phrase of which roughly translates into "I am a bagel".^note The intended meaning "I am a Berliner" is also a valid translation. In Real Life, the claim that people laughed because they understood it as "bagel" is a myth.[1] He is instantly transformed into a bagel, with the narrative making it clear that he died as a result of the transformation — Lyndon Johnson is immediately inaugurated as President and mention is made of bakeries in West Berlin fighting to be the one who provides the box used to serve as a coffin for the President's remains.
• Animorphs:
  • Demorphing in confined spaces can end with the subject accidentally crushing themselves to death if their natural state can't fit in the area. This is openly exploited in #22: The Solution by David when he captures the whole team, save Rachel, in cockroach morph by tricking them into a soda bottle and putting the cap back on. He ends up Outgambitted when Tobias, who he thought was dead, sets them free, allowing them to pull the same trick: they trap him in a cage just small enough to hold his rat morph but too small to safely demorph in, leaving him with no choice but to stay a rat until he's stuck that way.
  • Reused in #48: The Return, when Rachael is captured while in rat morph and imprisoned inside a reinforced box too small for her to demorph inside without self-inflicting fatal injuries. Unsurprisingly, this little trap's been masterminded by David as revenge on the Animorphs — albeit with help from Crayak.
• The Belgariad: Referenced when the protagonist learns Voluntary Shapeshifting. He's warned to form a perfectly clear mental image of the new shape, because if he forgets to include a heart, he probably won't have time to correct the mistake.
• In The Curse Workers, the rare Transformation Workers have the power to turn living beings into almost anything with a touch. Victims who have been transformed into animals can be restored, but those who've been changed into inanimate objects are dead from the moment of their transformation. It's for this reason that Barron and Phillip have brainwashed Cassel into serving as an assassin, as his powers allow him to kill anyone without leaving any kind of evidence.
• The Gone-Away World: On top of being a source of Reality Is Out to Lunch, the Stuff can also warp the biology of human beings immersed in it, transforming them to match their dreams and nightmares. However, most human beings don't know the finer points of anatomy, so many of the resulting mutants end up either horribly dysfunctional or dead. In one early case, a little girl dreaming of being a horse wakes up to find herself "hopelessly muddled with horsey parts" and unable to breathe with her new lungs, quickly asphyxiating to death.
• Goosebumps:
  • In the finale of Attack of the Mutant, Skipper bluffs the shapeshifting Masked Mutant by posing as a superhero named Elastic Boy and claiming that his only weakness is sulfuric acid. Naturally, the Mutant turns himself into a wave of the stuff. However, though the Masked Mutant has the power to shapeshift into any individual, animal, or object, he can't tolerate liquid transformations — as it means that he'll be unable to reform himself: as soon as he's finished his one failed attempt at attacking, he splashes into the carpet with a fizzle and dissipates into nothingness.
  • The Give Yourself Goosebumps title Little Comic Shop of Horrors has the protagonist entering a magic comic book store which allows readers to enter the comics themselves by transforming into a character from the book. However, leaping between stories too many times will result in the reader transforming into an inkblot. We see this happen with the protagonist's friend, and the Body Horror of his form melting away into ink is described in excruciating detail.
• The Hero Laughs While Walking the Path of Vengeance a Second Time: When the food Minaris and Kaito forced the slave trader that sold Minaris and the unbought slaves to eat turns them into goblins, it also turns out to be laced with a poison that kills goblins, this results in them dying via suffocation.
• The Legends of Ethshar has the spell "Bazil’s Irreversible Petrifaction", which kills the target by turning them to stone. There's also "Fendel’s Superior Petrifaction", normally reversible, but just as lethal if cast on someone who's high enough off the ground that their petrified body smashes on impact.
• The Lightbringer Series: While using luxin in general depletes the drafter's lifespan, going "Green Golem", a luxin user covering themselves in green luxin, results in the drafter's immediate death after a short period due to the amount of drafting required using up the rest of their life. Kip's survival from transforming as such is a miracle.
• Lilith's Brood: Aaor's depression overwhelms their biomanipulation powers, causing them to regress to more and more biologically simple forms; by the time Nikanj and Jodahs narrowly rescue them, Aaor is dangerously close to irrevocably dissolving into non-sentient single-celled organisms.
• In E.M. Goldman's novel Shrinking Pains, the main characters discover a literal Fountain of Youth in their backyard; on the upside, it works by temporarily halving their current age, meaning it's impossible to suffer a Death by De-aging. However, in the finale, the heroes are kidnapped and tied up while two of them are still regressed; they initially think they can just burst out of their restraints like the Hulk once the water wears off... but then Milo realizes that the ropes are too strong for a twelve-year-old to break through: instead, growing back up will just draw the ropes taut enough to slice open their wrists as they transform, leaving them to bleed out. And they've only got a few minutes left before they revert to their true ages.
• The Stormlight Archive: The Transmutation magic of Soulcasting can be used on living bodies to deadly effect, though it's deeply sacrilegious to do so. Jasnah Kholin wields this in battle, reducing her enemies to smoke, crystal, and fire.
• The Wheel of Time: The Dark One's power begins to leak into the world as his prison weakens, causing reality-warping "bubbles of evil" with deadly effects. One unlucky man turns into a swarm of beetles from the inside out.

Live-Action TV

• In one episode of Being Human (UK), George the werewolf needs to rescue his baby daughter who's been kidnapped by vampires. Reasoning that his werewolf form will be better at fighting vampires than his human form, he tricks himself into thinking he can see a full moon in order to artificially trigger his transformation. Unfortunately, he ends up in a hybrid wolf form that places more strain on his body than his pure-wolf form does and dies of organ failure once the transformation ends.
• Doctor Who:
  • In the classic series, The Master has weaponized this trope through his specialized weapon, the Tissue Compression Eliminator. It essentially shrinks the victim down to the size of a doll and kills them due to the Square-Cube Law, conveniently making it very easy for the Master to hide the body.
  • In "Ghost Light," after an entire serial full of nonlethal transformations experienced by the characters, Light uses his godlike powers to turn Gwendolyn and her mother to stone as punishment for having changed. For good measure, it's made abundantly clear that this is irreversible and lethal.
  • In "Partners in Crime", the Adipose pill transforms one pound of human fat cells per night into a living Adipose child. While normally this is mutually beneficial to the Adipose and the human subjects (who are taking the pills as weight-loss aids and unaware of the parthenogenesis since it occurs while they're asleep), in emergencies, Miss Foster is also able to trigger a total parthenogenesis — which fatally converts the entire human body into Adipose babies. Stacy ends up on the receiving end of this when Donna Noble accidentally triggers the parthenogenesis while she's still awake, forcing Foster to completely convert Stacy to dispose of the witness. Later, she attempts to do this to the rest of her clients when the Doctor threatens to expose her illegal breeding scheme to the Shadow Proclamation, but she's stopped before any deaths can ensue.
    • In the alternate reality of "Turn Left" where the Doctor died in "The Runaway Bride", Foster succeeded in killing millions of overweight Americans via similar methods without the Doctor around to stop her.
• Fringe:
  • "Transformation" kicks off with an unsuspecting airline passenger Marshall Bowman undergoing a nightmarish transformation into a giant bipedal porcupine; according to Walter, the process was so physically devastating that the victim wouldn't have survived for very long afterwards even if his initial rampage hadn't resulted in the plane crashing. As such, the Fringe team have to keep undercover agent Hicks from transforming through sedatives just so that he can live long enough to provide them with vital info.
  • In "Fracture," a rogue colonel has been dosing soldiers with a chemical that, when exposed to a certain signal, causes the subjects to instantly harden and crystalize into glass. In the unlikely event that this process isn't fatal, the crystalized victims then explode, showering everyone in the area with deadly shrapnel - including the couriers who were the real targets of this exercise.
  • "Nothing As It Seems" kicks off with Marshall Bowman's fatal transformation being repeated in the new timeline, but in this iteration of history, the transition is delayed until the plane safely lands - resulting in Bowman dying from the strain of the transformation instead of a plane crash. By the time TSA agents hear his screams, he's already writhing on the floor in his death throes. However, it's later discovered that it's possible for victims of the process to survive via a mixture of medication and human fat (stolen from cosmetic surgery clinics).
• Kamen Rider:
  • Kamen Rider Agito: Kamen Rider Gills has an imperfect version of the Agito transformation that causes cellular decay every time he uses his powers. He dies from this, and then gets revived, and then dies from it again, before his second revival finally comes with his powers getting stabilized enough that they won't kill him a third time.
  • Kamen Rider 555: The Faiz and Kaixa Drivers are deliberately engineered to kill their users in a failed effort to prevent a Phlebotinum Rebel. Faiz does it slowly, Kaixa does it very quickly; most Kaixa users die after the first use.
  • Kamen Rider Den-O: The Zeronos belt erases a random person's memories of the user each time they transform, which doesn't sound like this trope. However, in Den-O people's memories of the past are the past, so someone forgotten by everyone will cease to exist.
  • Kamen Rider Kiva: The Dark Kiva belt can be used to give an ordinary human the powers of a vampire king, but most people will die after using it even once. The biggest Badass Normal in the series manages three times before he dies.
  • Kamen Rider Fourze: Even though Fourze never kills his enemies, the Big Bad and his closest retainer die shortly after being defeated anyway, which Gamou admits is the consequences of having used their Zodiarts transformations for decades finally catching up to them.
  • Kamen Rider Wizard: The Beast Driver will let an ordinary human transform into a wizard, but the user will die when they run out of mana, which they have to constantly replenish by absorbing it from other spellcasters they defeat in battle. This wouldn't be so bad if it wasn't a Clingy MacGuffin and if it didn't slowly drain mana on its own over time; both are true, so your days are numbered as soon as you put on the belt.
  • Kamen Rider Gaim: Near the end of the series, Kaito gets infected with the Alien Kudzu that drives the series, leaving him terminally ill with the only potential cure being if he can claim the Forbidden Fruit and the godhood that it bestows on the one who eats it. In order to gain the power to do this, he undergoes a transformation into an Overlord using the infection, which another character notes means that while Kaito's days were already numbered, he's now only got a few hours to days left before he dies.
  • Kamen Rider Ex-Aid: Kamen Rider Genm's Dangerous Zombie Gashat inverts the trope: he has to die first to finish creating it, and then the Gashat locks him in the moment of his death, transforming him into an immortal zombie since he can't be dead twice.
  • Kamen Rider Build: By the time of the final battle, Kazumi has overdosed on Nebula Gas to increase his power level so many times that not only has his Last Chance Hit Point been revoked, but using Kamen Rider Grease Blizzard, which was meant to be a regular type of powerup for him, will instead kill him from the strain. He willingly uses Grease Blizzard anyway to face Evolt's mimics of his old friends, knowing full well that it will lead to his death.
  • Kamen Rider Zi-O: Geiz Revive, prophesized by White Woz as the only power that can defeat Zi-O, works by compressing and expanding time inside the user's body to give them Super-Strength and Super-Speed that can overwhelm Zi-O's Time Master powers through sheer brute force. However, it also leaves Geiz bleeding from the eyes after just one use: White Woz has avoided mentioning that the prophecy says he'll kill Zi-O and then die from the strain. Geiz eventually manages to bury the hatchet with Zi-O rather than continue to try to kill him, and with the prophecy broken, he's able to master using Revive to where it no longer hurts him.
  • Kamen Rider Revice: The Demons Driver goes through a vast number of users throughout the series because while it can be used by anyone, it wreaks havoc on the user's internal organs with prolonged use. Numerous contradictory explanations are offered for why this happens over the course of the show, with the final one being that all of the Drivers in the series are lethal to people who don't have the Half-Human Hybrid biology that the three main characters inherited from their father.
• For shapeshifters in the True Blood universe, prolonged Skinwalking (impersonating a human) causes great physical strain. When Luna Skinwalks as Steve Newlin during a newscast, it ends up killing her.

Tabletop Games

• Chronicles of Darkness:
  • Promethean: The Created: All Prometheans, including the nuclear-powered Zeka, can complete a Pilgrimage and transform into humans. However, the ex-Zeka then suffers radiation poisoning proportional to their former power level, which can be terminal.
  • Vampire: The Requiem: One Blood Magic rite lets a vampire transform their blood to poison to protect themselves from neck-biters. Ghouls can also learn it, but, not being undead, they react as most humans do to having their veins filled with poison.
  • Werewolf: The Forsaken: Zoonotics are people infected with a virus that gradually turns them into human-animal hybrids... but most never get that far. Unlike most forms of shapeshifting in this setting, this one has no magic backing it up, so the sheer damage to the zoonotic's body kills most of them before they ever get to the end stage.
• Dungeons & Dragons and Pathfinder:
  • The spell "baleful polymorph" can be used to transform the target into an animal that can't survive its current environment, such as a fish on land, but the target gains a bonus on the saving throw to resist it.
  • The spell "stone to flesh" restores a petrified creature to normal — but has a chance to kill them from the shock of the transformation.
  • Devils are formed from the souls of the damned. What many Hell Seekers don't know is that the process first inflicts Death of Personality through torture, destroying any hint of memory or individuality, and then reshapes what's left into a mindless lemure.
  • D&D 3.5 Edition: If a creature undergoes the ritual to become a Necropolitan without enough Experience Points to pay the cost, no sooner do they transform than they're Reduced to Dust beyond any means of recovery.
• In Feng Shui, while all Transformed Animals run the risk of reversion to their natural animal forms if they're exposed to magic, a Transformed Dragon that reverts to his or her natural dragon form in a magic-hostile juncture will die, because dragons in general can only live in places where magic is in abundance, something that the Ascended (who fear reversion and seek to keep the magic level low so that they can't be reverted) don't want.
• Warhammer: Unlike their mainstream counterparts, Chaos Dwarfs have the power to wield magic... but unfortunately, use of their power comes with a hefty price tag: it gradually transmutes their flesh into stone, progressively transforming them into statues. This process cannot be reversed, and all indications are that those Sorcerer-Prophets who have succumbed to the petrification no longer retain consciousness — to the point that the statues that line the road to Zharr-Nagrund are specifically referred to as "remains."
• Warhammer Fantasy Roleplay: Every creature has a secret limit on the number of Chaos Mutations it can gain before it degenerates into a mindless Chaos Spawn. If a Chaos Spawn gains a mutation that would transform it into a Chaos Spawn, it simply collapses into goo.

Video Games

• ANNO: Mutationem:
  • An effect that befalls victims of the Mechanika Virus is if they undergo a full transformation, they would die from the strain of losing their flesh, and those that survived would lose their minds until their bodies act entirely as mindless monsters.
  • In the bad ending, Ann's Moment of Weakness causes her to be completely taken over by Amok, causing an out-and-out Death of Personality and letting Amok free to unleash total destruction.
• Batman: Arkham Series:
  • Early in Batman: Arkham Asylum, the Joker unveils the first of his TITAN henchmen, an inmate beefed up to hulk-size by the eponymous performance-enhancing drug... only for the battle to end with the henchman abruptly dying of a heart attack. Joker then grumbles, "note to self: use stronger test subjects."
  • Downplayed in Batman: Arkham City. In the previous game, Joker dosed himself with TITAN in order to go One-Winged Angel, but now finds himself suffering from terminal blood disease as an aftereffect of the drug, leaving the Joker in a race to find a cure before he finally succumbs.
• Black & White - Battle of the Gods: The miracle "Verdant" permanently transforms everyone in its Area of Effect into ordinary livestock animals, destroying the original units forever. As it can wipe out an enemy army without penalizing the Karma Meter, it's effectively the Good god's answer to the Fireball.
• While members of the Wing Clan could freely transform into Great Birds and back in Breath of Fire I, by the time of Breath of Fire II, that ability has been all but lost. The only way to transform in that game is to undergo a ritual that invokes a one-way transformation, leading to a Death of Personality as their mind is reduced to that of a bird's. Party member Nina almost goes through with the ritual, but her little sister Mina pulls a Heroic Sacrifice and beats her to it.
• In Dragon Age: Origins, it's revealed that women infected with the Darkspawn taint aren't transformed into ghouls like most victims, but instead suffer hideous mutations that eventually transform them into Broodmothers. However, lore notes indicate that many would-be-Broodmothers end up dying of their mutations before they reach the final stage, hence why the Darkspawn are careful to keep the survivors out of harm's way despite their impressive strength. It's also why only two women out of Branka's entire House have survived being converted by the Darkspawn: Hespith, who is beginning to transform, and Laryn, who is a full-fledged Broodmother.
• The Elder Scrolls:
  • The Elder Scrolls IV: Oblivion:
    • Rona Hassildor hated becoming a vampire so much that she refused to drink blood and fell into a coma. You can deliver a cure, but she's so weak that she dies as soon as she becomes human again.
    • In the final quest, Emperor Martin Septim transforms into a draconic avatar of the god Akatosh to fight back the Daedric Prince Mehrunes Dagon. As soon as he wins, the divine power turns him to lifeless stone.
  • The Elder Scrolls V: Skyrim: The Wabbajack is a Magic Staff and artefact of the Mad God Sheogorath, which triggers a random effect when its magic hits something. These effects can include the target suffering a permanent Forced Transformation into an inanimate object, such as a sweetroll, a small pile of coins, some random books, or a large quantity of cheese. And there is nothing that can undo this transformation, nor is there any indication that the victim still retains their mind, making them effectively dead even if you don't eat the sweetroll.
• Final Fantasy XIV:
  • Near the end of A Realm Reborn, it's revealed that it's possible to summon a primal into oneself and control it. However, the effects of tempering still apply and eventually the person would lose their minds and suffer a Death of Personality if the summoner does not possess the Echo as Ysayle does. Elidibus implies that this would have been Yotsuyu's fate had the Warrior of Light not struck her down first.
  • In Shadowbringers, the "touch" of certain sin eaters can transform others into more sin eaters, resulting in a near complete Death of Personality and no way to reverse the transformation into a ravenous beast out to kill others. The Warrior of Light nearly succumbs to the same fate after taking in the Light of all five Lightwardens. Ryne manages to forestall the transformation long enough for them to cure themselves by expending it as a Blade of Light against Emet-Selch.
• In the finale of Indiana Jones and the Fate of Atlantis, Indy and the Nazis stumble upon the Colossus at the heart of the eponymous city, and Dr Ubermann decides to test its fabled capacity to transform human beings into gods. Regardless of whether it's tested on Indy, Sophia, or Ubermann himself, the candidate is turned into a glowing energy being that indulges in a bit of Reveling in the New Form... only to suddenly lose cohesion, claw at the screen in a blind panic, and disintegrate.
• The Legend of Zelda: Tears of the Kingdom: There is an ancient Dangerous Forbidden Technique called dragonification, which transforms a user into an immortal dragon by swallowing a secret stone. However, this eternal life comes at the price of losing the mind and identity, reducing the user to a mindless, animalistic beast. There is no known way to reverse the dragonification process, and is thus heavily discouraged even as a final resort. Zelda, who has been time-displaced into the past with the broken Master Sword, willingly chose this path to return to her present-time with a fully restored Master Sword for Link to defeat Ganondorf. Ganondorf, on the other hand, choses dragonification as a last-ditch effort to kill Link and destroy Hyrule, not caring if he has to sacrifice his body and mind to do it. At the end of the game, Link ultimately finds a way to reverse the dragonification process on Zelda while Ganondorf ultimately dies as a mindless Demon Dragon, his secret stone being destroyed by the Master Sword.
• Nethack: When a creature without the ability to control its transformations is hit by the polymorph spell or trap, there's a small chance it will experience "system shock" from the strain of the sudden transformation. This kills monsters instantly, while the player will take a random amount of damage between 1 and 30 (which can still kill you if you were at low HP or just very unlucky).
• In Phantasy Star Online 2, Adam Sacrid attempts to force humanity to evolve into more powerful Phantasms out of disgust for mankind's waste, want, war, and desires. The first person he tries to provide this "gift" to is mutated so horribly that he dies on the spot and disperses into aether.
• Sunless Skies:
  • People exposed to the light of the Clockwork Sun at close range find themselves beginning to turn to glass, forcing many of the workers at Azimuth to wear protective suits, and even this isn't enough to save them from accidental exposures. Individuals who've defied the Clockwork Sun are imprisoned directly in the light without suits, leaving them to transform until they go mad from the pain or die... which can take a very long time, unfortunately.
  • Downplayed in the case of the player character: "Pestilence," one facet you can acquire over the course of the game, reveals that you're beginning to turn to glass as well, and though it's progressing extremely slowly, it's indicated that it will eventually have terminal results - especially given that the Iron half of the facet features you suffering an Incurable Cough of Death.
  • Characters who make the mistake of being suckered in by Old Tom AKA the Amiable Vagabond will be condemned to plunge to the very bottom of the Well that bears his name, where they are transformed into trees - a process that essentially destroys their personalities and leaves them mindlessly worshipping the light for eternity. Depending on your choices, you can become a victim of this, ally yourself with Tom to sacrifice a skylark, or condemn Tom to the fate he evaded for so long.
• Undertale: In Undyne's Boss Battle in a no-mercy run, her Heroic Willpower becomes so great that she starts to generate Determination and transforms into Undyne the Undying. The feat is Beyond the Impossible for a monster... and monster bodies can't contain Determination, so you need only defend yourself as her new body melts away.
• Vermintide II: Chaos Warriors who accumulate too many Mutations degenerate into mindless, berserk Chaos Spawn with no trace of their former selves. This fate befalls Gatekeeper Naglfahr partway through his boss fight.
• Warcraft III: The Goblin Alchemist's ultimate ability "Transmute" turns the target to gold, dealing a One-Hit Kill and adding money to your cache.

Web Animation

• Discussed in the Kurzgesagt video "How to Make an Elephant Explode - The Size of Life 2", which opens with the narrator discussing an elephant being shrunk to the size of a mouse and a mouse grown to the size of an elephant. With the cells of their bodies no longer functioning at the size they were intended to, the elephant stumbles around before freezing to death, while the mouse briefly looks really uncomfortable before overheating and exploding.
• Watermelon: A Cautionary Tale: Jimmy consumes watermelon seeds and they start growing inside him. Over the course of the short, he becomes a watermelon-human hybrid, concluding by transforming into an inanimate watermelon. This might result in a Death of Personality, but it's left as a moot point as this final transformation occurs at the very moment that Jimmy jumps from a swingset: unable to course-correct, he hits the ground and bursts into pulpy chunks. And then the other kids eat him.

Web Comics

• El Goonish Shive: A flaw in Vlad's Voluntary Shapeshifting power made it so painful it almost killed him when he tried to use it. He's never tried again for fear that another attempt would finish him off; Ellen is eventually able to give Vlad a female form, but the newly-named Vladia still opts never to shapeshift — albeit as a personal choice.
• Goblins: Complains-of-Names carries a magic Shield of Wonder, which causes random effects to occur whenever it is struck with a weapon. During the battle of Brassmoon City, two of the city guards suffer this trope as a result of the shield's magic — one is transformed into an inanimate glass statue, and another is polymorphed into a ball of snakes that break apart and slither away. In both cases no indication is given that the guards survived or can be restored to their original form.
• Harbourmaster: Alu's first shift nearly killed her because it forced her to take conscious control of all her bodily processes, including heart and organ function. Species with the innate ability to shift can handle the cognitive load, but Alu needed emergency help to survive.
• The titular NIMONA has powerful shape-shifting abilities, which she can channel into healing any injury, but explicitly says turning into inanimate objects could kill her because it'd also transform her brain into inanimate matter.

Web Original

• SCP Foundation:
  • SCP-944, an anomalous Hall of Mirrors, has an area known as the Hall Of Fun that induces "permanent distortions" on visitors. Though the known civilian victim was lucky enough to survive despite being shrunk down to three feet tall, Foundation experiments revealed that the transformations can be fatal under the right circumstances. In one case, a D-Class happened to walk through one of the mirrors in this Hall of Fun, quickly growing to over seven feet tall, but the process of being stretched into a giant did serious damage to his internal organs, resulting in unconsciousness and death within ten minutes.
  • SCP-1575 is a fountain that transforms any animal drinking from it into a human being. Unfortunately, not only is the transformation incredibly painful, but it often ends up killing the subject due to organ failure or even massive bone fractures... or worse. In one particularly ghastly case, the Foundation submitted a dog for testing - only to realize too late that the subject's internal parasites would also be affected by the fountain waters: the poor animal died in mid-transformation when a seven-foot-long tapeworm with a screaming human face abruptly burst out of its stomach.
  • SCP-7955 is a human cultist converted into a shapeshifter through a Super-Empowering process known as the Rite of the Shining Brow. As he deliriously reveals late in the article, he was the first of the cultists to survive the rite in fifteen years, as the magic runes that previously enabled the rite had begun to fade, resulting in the would-be shapeshifters suffering fatal transformations in which "their eyes eat the body and the mind eats the eyes and all dissolves into meaningless meat."

Western Animation

• Adventure Time: Shoko, Finn's past life, was mutated into a weird worm-like creature after falling into a moat of radioactive Mutagenic Goo, and only lives long enough to reach the spot that would eventually become Finn and Jake's tree house. In a sad and ironic twist, Shoko was slightly happy when the fatal mutation regrew her missing arm.
• In Marvel's What If? episode "What If... The World Lost Its Mightiest Heroes?" the inexplicable murders of the would-be Avengers come to a head when the Hulk begins to grow out of control during his rampage at the university, expanding beyond his usual muscular growth to the point that he starts to swell up like a balloon — and then explodes. In the finale, it's revealed that Hank Pym is behind the murders, and accomplished this particular one by sneaking into Bruce Banner's body via a sniper's bullet and attaching a growth-disc to the Hulk's heart, causing it to grow out of control.

Real Life

• Sometimes, insects and other arthropods will die during the final stage of metamorphosis while transforming into adults. However, the ones who survive will usually only live long enough to mate (especially males) and reproduce (for females) before finally dying from old age, especially if they lose their ability to eat as adults - as is the case with the mayfly.
• Unlike frogs, toads are obligate land animals, yet must reproduce and be born underwater as tadpoles, only to lose their ability to swim and survive underwater as adults. As a result, a toad will drown if it finally becomes an adult and cannot reach nearby dry land in time.
• Some fatal illnesses, such as various forms of cancer and rabies, definitely qualify.

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