Body Horror/Western Animation

"Krusty: Well I got news for you, buddy: This ain't make up!"
 * Done in one of the Van Beuren Studios Tom and Jerry shorts (no, not THAT Tom and Jerry)--and Played for Laughs. In one episode taking place in the Swiss Alps, the duo eat a strange type of cheese that literally causes swiss-cheese esque holes to pop open in their body.
 * The Ren and Stimpy Show, in spades. Standout examples include Ren plucking exposed nerve endings out his mouth with tweezers, Ren and Stimpy being surgically joined together and so on. Particularly notable because, as a Gross-Out Show, the really horrible examples are shown via lovingly rendered and detailed paintings.
 * Aqua Teen Hunger Force uses this trope all the time. People get their skin ripped off, cosmetic surgery goes horribly, horribly wrong, a guy gets a body made out of eye-balls, the list goes on and on.
 * Batman
 * "On Leather Wings". Kirk Langstrom turning into Man-Bat in
 * Clayface I's couple of minutes of screen time in The Clay Face of Tragedy combine this with Tear Jerker.
 * What happened in Clayface II's introductory episode. Near the end, confronted with images of his acting roles, he starts morphing involuntarily in a Superpower Meltdown scene which can only be described as a cross between Tetsuo's final mutation and T-1000-in-the-smelter.
 * And before that, he'd been suffocating Batman with an attack that was lifted frame-for-frame from Akira. Tokyo Movie Shinsha worked both on Akira and this episode.
 * Poison Ivy, who made a habit of creating plant creatures that could pass for human. These often revealed themselves to be horrifying monsters. The best example of a horrific transformation is where Ivy rips the skin off of the upper torso of one of these creatures like it was a shirt, revealing the green flesh underneath. This is enough to cause onlooker Robin to start to heave (he's saved from actual puking by Batgirl).
 * "House and Garden", where Poison Ivy has appeared to reform and married a college professor and his two sons... only, it turns out the professor and his children are clones made from plant matter. And they only stay "human" for three days before turning into something that looks like Swamp Thing after a lawnmower accident.
 * At the end of "Bane," the titular muscleman gets a little too much Venom. His appearance in Batman and Robin absolutely pales in comparison.
 * Batman Beyond
 * Inque, a shapeshifting mutant who provides plenty of canon Fetish Fuel for the technician who releases her from a cryogenics facility. She dupes him in the nastiest way imaginable. She also likes to engage in Orifice Invasion and at one point tries to suffocate the protagonist by forcing herself down his throat.
 * In one episode, an android contorts his limbs horribly in order to chase Batman down an elevator shaft. The commentary mentions that this was an homage to Legend of the Overfiend.
 * "Splicers" is about this new fad of people (mostly teenagers) getting some animal genetics mixed with their body so they look like human/animal hybrids, including a bull, a snake, and a big cat (sounds really familiar for some reason) . Even Terry McGinnis involuntarily becomes an actual batman until he got better. However, the really bad part is when, after splicing becomes illegal since it makes people more aggressive, Batman goes to confront the guy who invented the process, who then turns himself into some weird Hawk-tiger-snake thing and after knocking away Terry's gun filled with mutagen cure all, Terry starts sticking the villian with multiple syringes. The villian then transforms into a disgusting creature that is even today one of the most disturbing things ever put into a kid's show. Unless you want to possbily be scared witless and lose some sleep, Take Our Word for It. Otherwise...
 * Jackson Chappell, who is rendered an obscenely muscled but brain-dead vegetable after an overdose of steroid patches.
 * The dog fighting club whose owner is using steroids on the dogs. The first test subject is... a bit overdone.
 * "Earth Mover" featured a rotting, living corpse, who was buried alive with a radioactive chemical that fused his body into the surrounding dirt. After years of being trapped underground, he looks like this. And keep in mind that he's still alive.
 * In Justice League Brainiac morphs Lex Luthor's body into some bizarre hybrid of biology and technology.
 * There's also an earlier scene in the same episode where Supergirl kills Galatea by... smashing a giant freaking power cable from the Watchtower's main reactor into her stomach. As Supergirl and an injured Steel limp away; you see Galatea twitching, her skin grey and a massive scar on her stomach.
 * The scene is made worse by the friggin Wilheim Scream she makes after the impact...
 * Some of Ben 10's alien transformations involve this. He grows an extra set of arms when turning into Fourarms, eyes pop out of his temple when he turns into Stinkfly, and so on. This is probably an Affectionate Parody of the scary alien transformation scenes so typical of horror films.
 * The mutations inflicted by Corrodium in the Ben 10 episode "Under Wraps" were particularly unnerving; monstrous, twisted, black shadows with glowing purple lines gouged across them. Later on, in "Be Afraid Of The Dark", when we actually see the mutations taking place as the entire populace of Earth is subjected to them, it's even more disturbing.
 * Kevin's transformation from emo preteen to giant Biological Mashup, complete with lots of screaming.
 * Perhaps this is why the Alien Force transformations are more boring less graphic...
 * The final part of Ben's intial transformation into Benwolf, in "BenWolf". Sure, it only lasted for a few seconds, but...
 * Invader Zim. In one episode he gets a huge pimple that appears to hypnotize everyone around him and then it explodes and floods the entire school. In another one, he collects organs from children and stuffs himself with them, replacing the organs with various, painful objects that he inserts in those kids' bodies. There is another episode where both Dib and Zim slowly transform into bologna. And then there is the episode where Dib has a huge hole in his head that absorbs nightmarish creatures, along with Zim. And, well, it's Jhonen's show after all, so every episode has its fair share of horror.
 * The Parking Garage Rat People in Game Slave 2 and when Zim's eyes BUBBLE and BURN in Walk Of Doom.
 * Catscratch has dealt with this in a few episodes- one being Major Pepperidge where Mr, Blik grows a second head (one that looks like him, but talks like a Jazz musician) and "Lovesick", where Gordon has an allergic reaction to broccoli where he puffs up really bad, gets a huge blood shot eye, a rash all over his body, razor sharp teeth and a drooling tongue in his mouth and a huge arm with razor sharp claws on his paws... This happens again at the end after Kimberly gives him chocolates which he also is allergic to.
 * Cow and Chicken tried to play this for humor. An episode of I.M Weasel had Weasel as a doctor who specializes in curing diseases; we see him with a guy who's got a case of Athlete's face (a foot sticking out of his forehead). I.R Baboon is stuck having to study parameciums (amoebas). Weasel takes a break for a while and I.R decides it is his time to shine - so he invents a so called "cure" for Athlete's face and uses it on the guy - it turns the guy into an amoeba-like form, he uses it to "cure" everyone else's problems and they get turned into amoeba-like things too. Weasel makes the real cure for the first time and tests it out on the Athlete's face guy but the athlete's face guy turns into something with only a head and a foot, so he tries again and it's successful. Thankfully, he shows up with the real cure and everyone returns to normal at the end.
 * One episode of Danny Phantom has the main character trying to duplicate himself, only to horribly, horribly mutate himself into an unholy concoction of body Nightmare Fuel: Little heads on individual fingers, mouths for eyes, eyeballs sticking out and so forth. On the other hand, it was Played for Laughs.
 * Dexters Laboratory has a direct American Werewolf parody called "The Laughing" (a reference to the werewolf movie The Howling) where Dexter becomes a "were-clown" after being bitten by a pair of dentures belonging to a clown performing at Deedee's birthday.
 * Futurama:
 * Parodied in "The Honking", which had Bender turning into a psycho werecar in one scene. But after a while he kind of gets used to it and it begins to actually feel quite nice.
 * Although it's partly Played for Laughs, the hip 80's CEO dying from boneitis in "Futurestock", complete with delightful bone-snapping sounds as his body constantly distorts into unnatural shapes. It doesn't help that when he dies, both of his hands pull his eyelids and lips back, freezing his face that way.
 * All of the underground dwelling mutants have some sort of deformity that makes them unpleasant to look at.
 * Gargoyles, "Metamorphosis". Elisa's younger brother gets transformed into a gargoyle-ish monster, and the only scientist who understood the process is killed. The episode ends with our cool veteran cop, Elisa, crying uncontrollably at the fate of her brother.
 * The Grim Adventures of Billy & Mandy has had more than a few episodes in which this has happened. One episode has Billy suddenly gets a pimple on his back which turns into a creature that acts like him who is dubbed Yupp Yupp. Billy is a king at this trope. Like the time he got his face ripped off. And in the intros, when the characters are brought from skeleton to muscle to skin.
 * Then there's the episode with the zipper, and he uses the zipper to remove his left arm and replace it with the cat's head, and in "Prank Call of Cthulu" when Billy's nose changes into a squid-like appendage which can flip up and spawn hundreds of insect-like creatures with Billy's head, sharp teeth and tiny tentacles. Screaming wildly, they all fly to Grim and attack him.
 * One episode had Mandy slowly transform into a Giant Spider, much to Billy's arachnophobic horror. For Billy's "son" Jeff, though, it's love at first sight.
 * A few episodes of Mr Meaty have dealt with this. Often it's due to the poor quality of the fast-food restaurant's entrees. In one episode, Parker mooches off most of the other characters and then gets infected with a tapeworm, "the ultimate moocher", 
 * In the episode "Parkerina", Parker eats too much Ms Meaty burgers and undergoes an American Werewolf In London style transformation into a girl.
 * An episode of The Real Ghostbusters had Egon turn into a werechicken, while another episode had the whole team undergoing a number of bizarre and sudden transformations after becoming "allergic to ghosts".
 * An episode of Extreme Ghostbusters had one of the lead characters becoming an evil clown-like creature. Then there's the episode "Crawlers" where people were turned into mutant bug creatures and another episode featured a group of monsters who used surgery to turn people into more monsters.
 * The Deadliners...argh, the Deadliners. Basically, they're Expies of Clive Barker's Cenobites who perform on unwilling victims "unnecessary surgery" that would make Ivo Shandor put away his tools in disgust. The worst part? The Ghostbusters are unable to put a dent into them until Garrett writes that they're vulnerable to the Proton Packs.
 * In ReBoot, anyone caught in a lost game is transformed into a slug-like "null".
 * What's worse is that it's implied (and in Season 4, shown) that Nulls are still somewhat aware, and apparently some residents use them to make balloon animals - complete with painful Null noises.
 * There's also what happens to people that get trapped in the Web without proper protection. Bob was only in there for a short time and his uniform was warped, his silver hair melted and turned black, his hands were charred black, and he had various scars on his neck and face. And he had partial protection from the Web too. Without that Bob would have ended up like Web Riders, which were in even worse shape.
 * The The Secret Saturdays episode "Ghost in the Machine" features a villain that creates a DNA reactor that merges living tissue. He places Zak, Fiskerton and Komodo into the machine, and... it isn't pretty.
 * Sev Trek: Puss in Boots spoofs the use of this trope on Star Trek: The Next Generation with an alien growing from a zit on Commander Riker's forehead. While the crew waste their time debating whether Riker's right to maintain his good looks overrules the PC Directive to respect all sentient life, the creature detaches and goes rampaging around the ship, murdering 47 expendable ensigns in the process.
 * Spoofed in several Treehouse of Horror episodes of The Simpsons, such as the one where Homer gets a hair transplant from Snake resulting in Snake's hair taking over Homer's body.
 * And also in the episode where everyone becomes what they're dressed as for Halloween. Homer becomes a headless horseman type character.
 * Don't worry. That was just a dream. Everything is perfectly fine. Well, except for that fog that turns people inside out.
 * Recently in "The Bob Next Door", which has got to be the most disturbing scene ever shown in an animated television show. In one of his escape attempts, Bob surgically removes the face of one of his cell mates and then switches it with his own, while still being fully conscious and screaming. The worst part is when Sideshow Bob stops at a rest stop and a waitress who's takes an interest in him, manages to pull off a loose thread used to keep his face on, causing his entire face to flap down, exposing all of his muscles and tissue. And then moments later, it happens again with his cell mate he switched faces with.
 * I'm guessing you haven't seen the movie this episode was a parody of...
 * The "Trapper Keeper" episode of South Park pays homage to the Akira transformation scene (complete with soundtrack); it involves Cartman's Trapper Keeper absorbing all of his school supplies, then his computer, then Cartman himself, turning him into a hideously gigantic bio-mechanical blob monster that threatens to destroy the world via the absorption of NORAD.
 * Poor Spider-Man underwent quite an unpleasant transformation into ManSpider in the "Neogenic Nightmare" arc of Spider-Man: The Animated Series. Later on, the Vulture absorbed Spidey's youth and powers... and also his unstable mutating DNA, meaning he sporadically changed fully or partly into the same creature. Another episode had Morbius turn into a bat thing.
 * To say nothing of the fact his original transformation, to avoid the "violence" of sinking his fangs into peoples' necks, gave him five sucking lamprey-like mouths in the palm of each hand. His typical feeding habit was to slap his hands over someone's face and... well, we'll let your imagination do the rest.
 * The Spectacular Spider Man has Connors' transformation into The Lizard, especially the part where instead of compressing slowly, his head partially implodes to form his new lizard head.
 * In an episode of Static Shock, the attention-seeking son of wealthy Edwin Alva uses gas from the Big Bang to grant himself various super powers so that he will gain attention from his dad as a supervillain. At the end of the episode, all of the containers for the gas pop at once, which causes him to transform unpredictably- the final form he takes is some sort of horrible, one-eyed, tentacley thing, but shortly afterwards reverts to normal and turns to stone.
 * Which only makes Alva's earlier remark about wanting a statue creepier.
 * In an episode of Teen Titans, Beast Boy is infected with a virus that turns him into a werewolf like monster. When he transforms for the first time he reacts like it's very painful.
 * When Red Star transforms involuntarily. Every molecule of his body going from solid to liquid to gas to plasma in a nanosecond.
 * The Tick (animation) episode "That Mustache Feeling". As quoted above.
 * In the original Transformers, this happens when Scourge tries to use the Matrix. His body develops grotesque bulges and warts and he falls to his knees screaming in pain as tears stream from his optical sensors.
 * Just...this.
 * Cheetor's transformation in Feral Scream part 2. It's slow, it explodes from pieces on his body, it's crazy, he has a nightmare about it... and he gains enough power to beat the crap out of EVERYONE when he's feral.
 * Blackarachnia's unnerving mutation from a promising young Autobot into a techno-organic freak in Transformers Animated.
 * How she found it in herself to subject Wasp... Make that Waspinator... to a similar transformation is beyond me, but the results are equally horrible.
 * She was trying to figure out exactly how she got changed so she could then work out how to change herself back. That, or she'd gone quite mad and decided to make her own army/family of technorganic beings.
 * She definitely wanted to find her way back. She said so herself. Good thing she never learned Sari's secret...
 * Had the show gotten a fourth season, there would have been an episode where the Autobots are forced to go face-to-face with Blackarachnia again, who now has started to make other Transformers part-organic. One of the organic robots the Autobots had to face in that episode would have been an Optimus Primal-esque robot named Primal Major. And the name of the episode? "Trukk vs. Munky."
 * Turbo Teen. The main character's face stretches out to become the grill of the car, his hands and feet become wheels, etc.
 * One of the reasons why The Marvelous Misadventures of Flapjack is such a profoundly disturbing series is because of the abundance of this trope.
 * The focus of the Teenage Mutant Ninja Turtles episode "Insane in the Membrane". After four seasons of losing body parts, Baxter Stockman finally obtains a new body via cloning. Soon enough, however, he discovers that it's unstable, as his limbs start deteriorating and melting off, ending with the result seen on the trope picture. Worse still, his mind is going with it...
 * In the world of Codename: Kids Next Door, chicken pox works a little differently than it does in the real world. The victim does indeed get raised sores all over her face and body... except the sores are tiny, living chicken heads bursting through the skin to wriggle and cluck wildly. It's intended as a Visual Pun, but plays out as pure Nightmare Fuel.
 * In Buzz Lightyear of Star Command, Ty Parsec is bitten by "energy vampire" NOS-4-A2, and the radioactive moon on the planet he's stationed on causes him to transform into a "wirewolf", which is basically a werewolf cyborg. The very first time Ty transforms, wires starts streaming out of the wound on his arm, and attach themselves to his neck. His eyes then grow to large, glowing red orbs, his jaw is stretched into a metal muzzle, and he grows a tail. It doesn't help matters that, from all his groaning and screaming, it looks and sounds exceptionally painful. As the episode progresses, his transformations get less and less creepy, but that first one always sticks out in your mind as pretty bone-chilling.
 * Exo Squad gives us Automutation Syndrome, which causes the sufferer to slowly melt into a puddle of goo.
 * What happens to Rourke after he gets slashed by a crystal shard in Atlantis the Lost Empire. Quite possibly one of the rarest (and most traumatic) examples in Disney film history.
 * In Happy Tree Friends this happens to Cub in one of the Halloween episodes. A curse warps the toddler into a tentacle monster.
 * An episode of SpongeBob SquarePants has Sandy's teleportation device screwing up and fusing Spongebob and Squidward into a weird mess. Then they later get un-fused, then re-fused with every other main character into a blob with people's heads sticking out of it.
 * The episode with the "small ray" takes Body Horror to a new level; when trying to reverse the ray, SpongeBob puts Squidward through an increasingly painful series of agonizing morphs — catching fire, being literally cut in half by scissors, having no skin... the worst transformations happened offscreen, with hideous gurgling sound effects that left the true horror to the viewer's imagination, which only made it worse.
 * "The Ick". It's a virus that causes green ooze to grow all over the victim's body. It's contagious on both touch and ingestion. Somehow, Squidward doesn't realize he's scratching a Ick-y spot, and a restaurant full of diners don't notice they're eating it. The only other known symptom is itchiness, but you have to wonder why Krabs called the SWAT team. And why they called the HAZMAT squad.
 * In the "strike" episode, SpongeBob is stuck to a window. When Squidward tries to pull him away, he ends up tearing his entire face off and you can see his internal organs.
 * There's a rather gruesome scene in "Plankton's Regular", where SpongeBob is lying in front of the Chum Bucket's door, and the regular customer opens the door over him, scraping off his face in the process. It doesn't get really disturbing until he sits up, and you can see all the (rather detailed) muscles of his face exposed. * shudders*
 * There's also "I Was A Teenage Gary" where Spongebob and Squidward accidentally get injected with snail plasma and turn into snails.
 * Also, the episode where jellyfish jelly becomes a popular condiment on Krabby Patties. Mr. Krabs captures a bunch of jellyfish fish so he can mass-produce the stuff. His factory jelly-extracting equipment is absolutely brutal on the poor jellyfish.
 * One episode was based almost completely around Spongebob and Patrick watching a Mermaidman and Barnacle Boy episode in which they fight all of the shows villains. In it The Atomic Flounder uses his Atomic Touch ability, which causes Barnacle Boy to sprout a third arm from his shoulder, which proceeds to beat him up. It gets even "better" once he's knocked out. The hand then deforms and sprouts a face, before proceeding to take over Barnacle Boy's body.
 * The episode "The Inside Job" is full of this trope. Losing sight and hearing, a complete version of Spongebob's house made of brain including Gary, and two scary transformation sequences.
 * "We're like brothers...only closer."
 * On The Fairly OddParents, Elmer has a boil on his face that has a mind of its own, and it's an evil mind. Yes, it's played for laughs. But it's pretty disturbing if you think about it.
 * This also happened with Chris' zit on Family Guy, which actually held him hostage for a while.
 * Also on Invader Zim, though the boil didn't come alive Zim did paint a face on it, and it did hold everyone's attention long enough for Zim to attempt one of his master plans.
 * The EVOs from Generator Rex are made of this. Nanites are inside every living thing, and can turn it into a monster at any moment, pretty much at random.
 * There's also the episode where Rex absorbs too many nanites, which leads to him losing control of them...which, in turn, leads to horrible metallic growths with a mind of their own.
 * Body Horror is pretty much a major thematic element of this show. It's not a cartoon for the squeamish.
 * In the Legion Of Superheroes cartoon, Timber Wolf undergoes a forced transformation into a werewolf-man, which also gives him super powers. The others experience some form of this, such as Bouncing Boy being splattered against a wall(don't worry, he lives) and them being transformed magically into monsters by evil wizard Mordru.
 * One of the early episodes of Inhumanoids featured Sandra Shore, The Chick of the team, being infected by one of the titular villains and turning into a hideous monstrosity.
 * Adventure Time . The show has several of these, but the most prominent would have to be in "City of Freaks," when the Magic Man turns a bird inside out, organs and all, and it attempts to clumsily fly off, eventually just bumbling it's way along. And it's never seen again.
 * "I'm in my happy place."
 * "As you can see, my skin is starting to turn blue. My body temperature has been lowering at a supernatural rate, to what is now about thirty degrees Celsius. I don't know when it will end... I'm really scared."
 * The animated G.I. Joe movie is the king of this trope. We've got Cobra Commander being revealed  and , an entire hidden civilization based on particularly nasty organic technology, spores that look to rather painfully mutate all of humanity. Oh, and "Onccccce... wasssss a man..."
 * 1980's Jonny Quest episode "Creeping Unknown". Mr. Trudge is slowly turning into a plant and has green, gnarled branches for hands. He also attempts to turn other people into human-plant hybrids.
 * The Real Adventures of Jonny Quest had some pretty good examples as well. One episode had some poor guy turn into a werewolf because of a genetic condition. It does not sound pleasant.
 * Avengers Earths Mightiest Heroes gave us the two part episode "Gamma World", where you saw ghe Avengers mutate into Gamma monsters.
 * Gene-slamming in Street Sharks is rather nasty, what with growing the extra limbs and the screams of pain and whatnot. Bonus points to the first transformation, when the one guy's hand starts to change before the rest of him does.
 * Star Wars the Clone Wars:
 * Savage Opress undergoes a ritual that causes his body to mutate into a much larger and more ferocious looking form. What makes the scene horrific, however, is that you can hear his bones extending, and see his horns grow longer out of his skull. It's a good thing he was unconscious at the time, because one gets the impression that he'd be in agonizing pain if he had to go through all that while conscious.
 * Obi-Wan's transformation into "Rako Hardeen" involves his skin visibly warping, and his skull reshaping itself to create his new face. Judging from his reactions, the procedure was very painful.
 * Phineas and Ferb is usually a very tame show as far as nauseating jokes are concerned, but the episode "Canderemy" is an exception. In a nutshell, Doofenshmirtz builds an Inator that combines to objects together. Candace and Jeremy were lucky enough only be attached at the hip. Everything, and everyone else? Not so much.
 * My Little Pony Friendship Is Magic has the evil queen Chrysalis, who has holes in her legs. It looks kind of... disturbing.
 * Super Robot Monkey Team Hyperforce Go! has this in a few places.
 * One prominent episode is Super Fun Meat World. Said meat contains an alien parasite which causes anyone that eats it to horrifically bloat, as well as becoming addicted to their food. Also even a tiny bit of said meat can become a Blob Monster to take care of anyone who knows too much. As if that wasn't enough, the process to reverse the main characters transformation goes a bit wrong, causing his face to temporarily melt in multiple ways. The villain is also a 30 foot tall gangsta' colon; the episode managing to be both pure Body Horror and incredibly silly at the same time.
 * The power of the Dark Ones can also have this effect. Too much exposure to it transformed the kindly Alchemist into, and then there's Mandarin who was Swallowed Whole by one of said abominations. He eventually got better, but the combination of said energies and pure stomach acids were not kind.
 * Parodied in The Mask. Stanley is in Dr. Pretorius' base, having found out that the madman has kidnapped the mayor. On a workbench, we see a red lump of something with a glass dome over it. Stanley immediately exclaims, "Mayor Tilton!", and an exasperated Pretorius says, "No, that's hamburger meat!" Crisis averted...until Pretorius turns the uncooked hamburger meat into a living, snarling monster.
 * The Simpsons: Played for laughs in "Homer's Double Bypass":
 * The Simpsons: Played for laughs in "Homer's Double Bypass":