Painful Transformations in Western Animation.
- In Adventure Time: Fionna and Cake, Golb rips The Lich apart and forcefully transforms him into one on the geometric shapes that orbits around Golb. The Lich screams in horrific pain and panic as it happens.
- The American Dad! episode "Stan Goes on the Pill" has a scene of Stan transforming into a woman as a Shout-Out to An American Werewolf in London.Francine: Ugh, I have a headache from all this screaming.
Stan: Well, not to compete with you, but I have a headache from my skull changing shape. - The Avengers: Earth's Mightiest Heroes:
- The Avengers (except Thor who is The Immune due to being Asgardian) endure some painful transformations in the episode "Gamma World", as part of The Leader's plan to turn everyone in the world into Gamma-irritated monsters. Iron Man's pain receives particular emphasis, as the animators show the toll the gamma blast takes on his shrapnel-embedded heart.
- Simon Williams' transformation into Wonder Man, in another episode, seems unbearable as well. The other characters mention that Simon became the only person to survive the process.
- Ben 10:
- Kevin's transformation into his Shapeshifter Mashup form ends with him screaming in agony.
- Ben's final stage of transformation into Benwolf. For most of the episode, he'd just been gradually getting furry and wolflike, then... ouch.
- The 2006 revival of Biker Mice from Mars has Stoker change into a rat-like beast called Stoker Rat when under sunlight. The transformation first occurred in the episode "Changes" and happened again in "British Invasion". The transformation is an ode to the transformation scene from An American Werewolf in London.
- Codename: Kids Next Door: During the episode Operation G.R.A.D.U.T.E.S, Father invents a device that turns all the of the members of the Kids Next Door into animals and the transformations are not pretty. Numbuh 5, who was turned into a gazelle, was screaming in pain until the point she no longer could and the rest of Sector V was also shown to be in a large amount of pain.
- The Cuphead Show!: The Christmas Episode/Villain Episode "A Very Devil Christmas" has the Devil go through an agonizing transformation... into Santa Claus. After which he's tasked with Subbing for Santa lest he stay that way forever. Yeah, It Makes Sense in Context...
- Danny Phantom actually has five instances, all Danny. The first and last sets of two are all seen as excruciating agony. The middle one is Nightmare Fuel and what follows is just as disturbing and really should have earned a higher rating.
- Dexter's Laboratory has Dexter transform into a clown whenever he laughs because another clown's dentures flew off and bit him on his funny bone at Dee Dee's birthday party. It's undone at the end when Dee Dee takes up miming lessons to subdue his clowning around and causing destruction throughout the city, then taking him back to the lab to administer an antidote.
- Garfield: His 9 Lives, life 7
(about 3 minutes in, and be grateful the final takes aren't shown). - Gargoyles:
- Derek has a particularly painful one when he turns into a mutate.
- Demona is eventually given the ability to become human by day instead of stone. The change is agonizing both ways. It was actually painless the first time, though, as Puck, who gave her this ability, wanted to surprise her. When Macbeth (to whom she's magically connected) is nearby, he feels the transformation too.
- Played for Laughs in the first episode of Invader Zim. As a machine gives Zim his human disguise (offscreen), he screams "Why does it hurt?!" (For the record, his disguise is a wig and a pair of contacts.)
- Whether or not putting on or removing the titular artefact in The Mask varies from episode to episode. Sometimes, the transformation looks very painful, with applying the Mask causing it to melt onto Stanley's face and turn his whole head into a mass of greenish-brown flesh that ripples and flows unnaturally around a distorted, bug-eyed, pain-filled grimace, and removing it requiring the Mask to pull his face as it stretches like rubber and finally gives way. Other times, the transformation appears almost effortless, with removing it in particular being done in a snap.
- Parodied in South Park Season 14 Episode 9 It's a Jersey Thing, when Kyle "transforms" into his Jersey self, "Kyley-B" when South Park is being invaded by New Jersey folk.
- Spider-Man: The Animated Series: Spider-Man himself undergoes this during the "Neogenic Nightmare" arc. It starts with simple bouts of Power Incontinence, and is then followed with debilitating pain in his sides, which he describes as feeling like "getting a massage from Wolverine — from the inside." Finally, he sprouts four extra arms before painfully transforming into a monstrous half-man/half-spider creature. An alternate Man-Spider shows up in one of the later episodes when Spider-Man has to team up with his alternates. That Peter accepted the mutation fairly well, but the villain forced him to be Man-Spider at the worst time. Man-Spider's later fate is unknown but presumably he's back to normal.
- SpongeBob SquarePants:
- In "I Was a Teenage Gary", SpongeBob is accidentally injected with snail plasma by Squidward to cure his pet snail, Gary. Squidward assures SpongeBob that he'll be fine, and he believes him. But the next day, he starts exhibiting snail-like behavior, including meowing, eating snail food, and walking slowly. His fears are turned into reality as he goes through the gradual transformation into a snail.
- In the episode "Mermaid Man and Barnacle Boy IV", SpongeBob accidentally puts Designated Victim Squidward through a series of increasingly painful and graphic transformations (burning, being cut in half, being skinless, and some that were so grotesque they were only heard offscreen as sound effects that don't bear thinking about) while trying to undo the effects of a "small ray".
- "The Inside Job" has Plankton going inside SpongeBob's body and attaches a sucking helmet to his heart to gain information about the Krabby Patty formula. This ends up causing him to turn into a small version of SpongeBob, with a sequence complete with eyelashes breaking through his skin and his teeth shattering to make way for two goofy buck teeth. Then, at the end, Sponge!Plankton gets attached to Patrick and we get a similar sequence where he becomes a dumb pink plankton.
- Star Trek: Lower Decks: In "Moist Vessel", O'Connor's ascension is an ordeal of constant agony where he can feel his physical form burning away as his mind is overloaded with the secrets of the universe.
- Steven Universe: Future: While at the beginning he just glows pink, in the second half of the epilogue, Steven's body starts to randomly swell up whenever he is in a great emotional distress, because of his untreated trauma and PTSD caused from everything he experienced in the original series. It reaches a breaking point in "Everything's Fine", where he has a spectacular mental breakdown, which the episode ends with pink spikes violently bursting out of his back, starting his corruption into a Kaiju-like rampaging monster.
- Street Sharks: Getting turned into a mutant always involves a good bit of screaming. Makes sense, considering that occasional extra limbs are grown and all of them gain a good amount of extra muscle mass.
- Teen Titans (2003):
- Most of Beast Boy's transformations appear painless, except for the episode when an accidental shower of chemicals caused him to morph into a Hulk-like werebeast against his will.
- "Snowblind": Red Star definitely has this problem.
- Teenage Mutant Ninja Turtles:
- Donatello's secondary mutation from the "Good Genes" arc of Teenage Mutant Ninja Turtles (2003). The transformation itself — which happens after a long illness — is fairly brief, but still enough to leave him screaming in pain.
- In the 2012 cartoon, apparently, getting doused in Mutagen and undergoing a mutation is agonizing if you were human. When Mutagen Man is created, he screams that it burns.
- Transformers:
- If one of the eponymous Transformers hasn't transformed in an exceedingly long time, or is banged up badly enough, transforming can hurt like hell, or, in extreme cases, be fatal.
- When Waspinator is put into Blackarachnia's transwarp machine in Transformers: Animated, he screams and his hands can be seen clawing at the machine. Blackarachnia casually comments that it might hurt a bit.
- Most upgrades the Transformers experience in Beast Wars seem to come off this way. Everyone's transition to Transmetal in the season 2 premier was accompanied by screams and bodies collapsing. The changes to Transmetal 2 seemed even worse.
- The Transformers: In "The Burden Hardest to Bear", Scourge takes on the Matrix of Leadership, which makes him extremely powerful, but warps his body, which looks extremely painful and even makes him cry.
- Matt from W.I.T.C.H. always has to brace himself before turning into Shagon.
