"He's still out there behind our shed. He'll never move again."
In the Joe Oriolo Felix the Cat cartoon "Stone Making Machine", The Professor tries to pull this on Felix just for the heck of it—he tries to capture Felix and turn him into a stone statue with the eponymous machine. But when Rock Bottom goes off to kidnap Felix, he accidentally grabs a stone statue an artist made of Felix in his house (it was dark, so Rock couldn't see that well) and Felix, who thinks he's stealing his statue, trails behind him. They find out their mistake and capture Felix (who had snuck into the lair) and try to turn Felix into a statue for real, but Rock Bottom, who was supposed to keep Felix from stepping outside the machine, turns his back because he can't bear to watch Felix get turned to stone, which gives Felix a clear shot at an escape before the machine activates.
In the Fantastic Four 90's animated series, Doctor Doom uses his new cosmic powers which he stole from the Silver Surfer to inflict this on Ben Grimm by slowing his metabolism down to the point where he can't move or speak, but is still aware and becomes in Doom's words a "living statue" for the rest of his life.
American Dad!: The ninth season episode "Familyland" has a self-inflicted, deliberate example in Roy Family. When he created the titular theme park thirty years previous, he froze his body right in the center of the park in the form of a statue of himself. The entire time, he was fully conscious of his surroundings, which he did on purpose so he could watch the park come to fruition; he nonchalantly admits to Francine upon thawing that "it was awful." He willingly returns to that state at the end of the episode, but unfortunately, he only remembers he has to use the bathroom right before he's frozen again...
The Fog of Lost Souls from the Sequel SeriesThe Legend of Korra is another nasty aspect of the Spirit World; a spirit prison for humans, it slowly drives its occupants insane with visions of their greatest fears and failures. Worse, while humans can die of old age and starvation in the Spirit World, the Fog keeps its victims alive and healthy so they can continue to stew in their madness. Zhao has been imprisoned for almost seventy years, and he's been reduced to wandering the fog ranting about how he will defeat the Avatar.
The fate of Donald Duck at the end of "Donald's Snow Fight", where he gets frozen alive. And the audience is supposed to sympathize with his nephews - who put him in that state - just because he beat them fair and square in the snowball fight earlier before they got their act together.
Satan's Waitin': Sylvester's eternal torment in Hell is a pit of fire full of demonic bulldogs.
Though if you think that's bad then just wait until you hear what happened to Blurr. He was crushed into a cube by Shockwave and was confirmed to still be alive, then he was supposedly put into an incinerator soon after though there is some debate amongst the fandom about this.
Although one of the comics shows Cliffjumper carrying the cube around with him, so he apparently saved from that last bit. Unfortunately, Cliffjumper doesn't seem like he knows how to get Blurr back to his old self...
In an episode of the Legion Of Superheroes, the wizard Mordru is wrapped in a metal cocoon and sunken to the middle of the planet. Pretty harsh when you consider his eyes were still moving as he was buried, and the planet probably has a molten core... so either he is buried alive or melted. Pretty harsh for a team that works with the police and United Planets.
In "Sneak Peek", TV personality Ian Peek intangibility device finds the effect spreads to his body without the device being engaged. In the end, his Power Incontinence winds up causing him to phase through Batman's hands, through the floor, and into the Earth. The best case scenario is that the lack of Required Secondary Powers will mean incineration by the mantle, or death by suffocation, starvation, dehydration, or at least old age. If not, he's permanently phased into the core of the earth. Forever.
Another villain, Inque, can shapeshift by turning into liquid and reforming. In "Disappearing Inque", Aaron Herbst, a guard at her prison who had a crush on her, is sweet-talked into helping her, but wants powers like hers in exchange. She gives him an incomplete version of the formula, leaving him an immobile half-liquid blob. His guard is seen talking to him just as he once did with Inque, hinting that history may repeat itself, but that's unrealistic: he can't move, and doesn't know enough about the formula to instruct her on how to fully Inque-ify him were she to agree.
In "Earth Mover", Tony Maychek fused with the Earth itself, for years. His episode centered on his anger at his unjust fate and wanting to see his daughter again. Thankfully, it gets better for him, since he found a way to control the Earth itself, then found release when he was finally killed in a cave-in.
In "The Winning Edge", it's revealed that Bane's body has withered away after years of Venom use, and he now lives in a nursing home under 24-hour life support, ironically staying alive only through the continuous infusion of more Venom.
Justice League Unlimited is usually nicer to its villains than Batman Beyond, but makes an exception for Mordred: Morgaine Le Fay's spell gave him eternal youth and life, but he's stuck as a child. When tricked into making himself an adult (thus causing him to disappear, as he'd cast a spell that teleported all adults to another dimension) it turns out that by breaking the youth spell, "all he has is eternal life." He's 1500 or so years old and counting, showing every bit of it, and is now essentially immobile in a chair at his (still-youthful) mother's home. And it's only going to get worse.
At the end of the two-parter "The Once And Future Thing", Chronos winds up permanently trapped in a timeloop, being forever berated by his shrewish wife. At first glance, Chronos does not appear to be aware of his fate, but if you look closely when Chronos presses the button on his belt, you can see that between screen-flashes there is a one-frame image of Chronos with a look of horror on his face.
In most adaptations, the Joker's signature venom kills people. However, to keep the body-count down, animated adaptions like Batman: The Animated Series and The Batman, Joker venom "merely" paralyzes people with a huge grin, or leaves them unable to stop laughing. More than one fan has observed that this is far, far more disturbing. As Alfred put it in the first episode of the latter series,
Alfred: Aside from the ghastly grimace, [he's] fit as a fiddle. The poor soul simply seems to be a prisoner in his own body.
Fortunately, Batman is able to find a cure by the end - this time.
Poison Ivy does this to a bunch of rich industrialists she blames for the destruction of the earth's various plant species, and natural habitats. She lures them to a resort and spa, floods their bodies with a mutagen by tricking them into eating food and water loaded with it, and eventually they turn into human trees. Fortunately Batman is able to save everybody.
Then there's Grant Walker, a Walt Disney-esque billionaire who, in addition to building a "perfect" society on an island of his creation, convinces Mr. Freeze to give him the same mutations as Freeze himself, allowing him to live forever. However, after Batman convinces Freeze to stop Walker from freezing the rest of the world, Walker ends up trapped in a block of ice, lost at sea, COMPLETELY AWARE OF EVERYTHING AROUND HIM, YET UNABLE TO FREE HIMSELF OR EVEN MOVE FOR THE REST OF HIS IMMORTAL LIFE. As is to be expected, the last we ever see or hear of him is his anguished scream of horror, a scream that no one else can hear.
Well, he was. A comic followed up his story by showing that he managed to get out (cause icebergs do melt ya know?) and tried returning to Gotham to get revenge upon Freeze after finding out that Freeze's condition had destroyed most of his body and the same thing would happen to him eventually. He was captured and imprisoned after Freeze almost killed him.
Bender seems to be programmed to not be bothered by this sort of thing. Besides the "Roswell That Ends Well" example, in the "Bender's Big Score" movie, Bender is perfectly happy to spend a total of millions, possibly billions of years hiding in a cavern with only his own time duplicates for company. A holiday What If? episode also had him buried underground for 500 million years and coming out completely unaffected.
It could also be that Bender's intense narcissism enables him to spend however long he needs spending quality time with only Bender for company.
"A Head in the Polls" begins with the collapse of a titanium mine, trapping all the robot workers inside (some of whom are seen pinned in the entrance, still twitching). The proposed rescue plan is to "pave over the area and get on with our lives."
The victims of the Brain Slugs are completely conscious.
In the Sonic SatAM Saturday morning cartoon (as well as Sonic Underground, and the Archie comics), roboticizing a person meant turning them into a machine, eliminating their free will. However, their minds still function, causing them to be used as slaves to Robotnik, knowing what's happening but incapable of doing anything about it.
The fate of Ch'rell the Utrom Shredder in the 2003 Teenage Mutant Ninja Turtles cartoon. After having battled and defeated him many times in the past only for him to return for a rematch later every time, Splinter and the turtles, despite an interruption by Ch'rell, who beats such stuffing out of them that they spend the next episode recovering from their wounds, successfully destroy his spaceship and, along with him, Karai, and Dr. Chaplin, are transported to the safety of the Utrom homeworld by the Utroms themselves just before the ship explodes. There, everyone is attending as the Utrom council places Ch'rell on trial. The council finds Ch'rell guilty and sentences him to eternal exile to his new home on the ice asteroid belt of Mor Tal, where he does very little but let loose a furious Big "NO!". Later, he was found frozen in ice by the Laughably Evil 1987 Shredder in Turtles Forever, which was proof that this was Ch'rell's fate, a fate eventually undone by the 1987 Shredder himself.
In the original cartoon, this was Baxter Stockman's ultimate fate - trapped in limbo between dimensions.
Master Shake wanted to inflict this onto Happy Time Harry in an early episode of Aqua Teen Hunger Force, after finding out that he's suicidal.
In Thomas the Tank Engine, Duke warns Stuart and Falcon with the story of a misbehaving engine that was turned into a generator, immobilizing him forever. It gets even more horrifying when the Fridge Logic sets in as he was presumably buried alive along with the rest of the old railway, trapped underneath several feet of dirt and unable to call for help.
Duke himself was abandoned in his shed, which was covered over by nature and buried for many years, until he was unearthed in "Sleeping Beauty".
"The Sad Story of Henry" ends with Henry left to rot in the tunnel for "always and always and always". The narrator even mentions how Henry has no steam left to answer with.
In the special Misty Island Rescue, Thomas and the three Logging Locos get trapped in an underwater tunnel (Bash, Dash and Ferdinand running out of fuel) with nobody knowing where they are.
In the final episode of Kong: The Animated Series, De La Porta's life force is sucked out to free Chiros. Though his life force is returned when Chiros is killed, his spirit has been broken by the ceremony, leaving him in a permanent state of shock that his doctors don't think he'll ever recover from.
In "Blast From The Past", Sniffles accidentally causes an eternal time-loop of himself, Lumpy, Cuddles, Giggles, and Toothy dying over and over again.
In "Tongue Twister Trouble", Sniffles gets frozen alive.
In "House Warming", Petunia is reduced to a burnt bloody mush that can barely even move.
In "By The Seat Of Your Pants", Handy (who already lost both of his arms), gets his legs chopped off by Flippy, rendering him immobile.
In "Dream Job", Lumpy inadvertently tortures Sniffles by flipping through various channels of the TV attached to his dream helmet, forcing him to go through numerous deaths until he overpowers the TV and renders him catatonic.
The "Squid On Strike" episode of SpongeBob SquarePants ends with Mr. Krabs punishing SpongeBob and Squidward by making them work for him... FOREVER. The next scene cuts to them reduced to skeletons and they're still working.
"Perfect Chemistry" ends with Plankton being stuck in a corked bottle, in Mr. Krabs' safe, where no one can hear him.
In "Krabs a la Mode", Mr Krabs traps Plankton in an ice cube.
The episode, "Home Sweet Pineapple" ends with Squidward trapped under Spongebob's house, unable to see anything or move.
The Penguins of Madagascar has Skipper's previous teammates, Manfredi and Johnson, as exhibits at an aquarium... and when he flies past them, he can't hear them.
The ending of the Silly Symphonies short Peculiar Penguins, ends with the shark, who was chasing the protagonists for half the picture, with a very large rock falling into his belly, trapping him at the bottom of the ocean to possibly starve to death.
Wild Kratts has Donita Donata who specializes in "living jewelry", i.e. living animals frozen in suspended animation and attached to horrendous fashion. And yep, they're still conscious.
Paradox in Ben 10: Alien Force found himself trapped in the event horizon of his time tunnel for hundreds of thousands of years, unable to escape or die.
In an episode of Darkwing Duck, "U.F.Foe", Darkwing finds his brain taken out by aliens and his body controlled by remote. Although he has no mouth (or beak) and we "hear" his screaming thoughts, amazingly he can still kick ass as he destroys the computer brain and saves Launchpad from the same fate!
Similarly, in an episode of DuckTales, the Beagle Boys manage to take control of Gizmoduck's armor by remote - while Fenton is still wearing it. He's not at all happy with being forced to rob his own employer in broad daylight... or stealing his crush's car, for that matter.
In "Northwest Mansion Mystery", the people at the mansion's party are turned into wood by the Monster of the Week; in particular, Dipper gets frozen mid-scream, knowing what was happening to him. Even after the effects are reversed, he takes in a large gasp of air.
After his Deal with the Devil in "Sock Opera" Dipper is forced to watch his own body be controlled by a demon, and no one can see or hear the real him.
Another Black Comedy moment in "The Deep End" shows a little boy trapped in a pool grate having to watch all the other kids have fun in the pool while he remains stuck. The end of the episode shows how he has been in there for over a year.
And then, there's "Weirdmageddon 2", in which Bill Cipher turns the inhabitants of Gravity Falls to stone and then assembles their contorted bodies into "massive throne of frozen human agony". "Don't worry! They're not conscious any more. Probably." Yes they are.
The Chronicles of Riddick: Dark Fury has the eponymous hero go up against a madwoman who "collects" criminals and keeps them awake but practically frozen in artistic poses as part of a grotesque, living gallery. She created a type of stasis that slows their bodies down to a crawl but lets their minds be fully functional. It takes them a day and some excruciating pain to even blink their eyes.
In The Fairly Oddparents, it is eventually revealed that everything a child wishes for are put into "storage" in giant lockers. This includes any wishes that result in sentient creatures. And since they are immortal, they are stuck in a small, dark area forever. The fact that no one bats an eye at this says something.
Timmy's undone wishes are even worse, given that they had to abandon the locker concept entirely and port them all to an island (possibly a commentary on his tendency to hit the Reset Button every episode). It's revealed that the leader of this island is Timmy's imaginary friend Gary, who also fit this trope in his first appearance. After Timmy got Cosmo and Wanda as his fairy godparents, he forgot about his friend... but Gary never forgot about him, and was trapped inside Timmy's imagination, fully aware that he was being ignored. It's no surprise that he went for the revenge route.
The fate of Turbo Thunder's parents in Wishology. Luckily, Timmy saves everybody in the end, including them.
"Paralytic fluid" in the Æon Flux episode "Ether Drift Theory". The Habitat laboratory is submerged in a lake of said fluid, which paralyzes those who fall in it, with no hope of rescue. But they are still conscious.This happens to Aeon herself at the end of the episode. The last scene of the episode is of Aeon, paralyzed in the fluid, as the two halves of the item that would neutralize the solution slowly float in front of her eyes, collide, and go in different directions.
In The Venture Bros. episode "Return to Spider Skull Island", Doctor Orpheus deals with two Jerkass rednecks by trapping their souls in a Homeboys figurine. They can actually be heard screaming.
The Secret Saturdays: In one episode, the family face against a warrior king whose thirst for power long ago could not be quenched. Seeking to use the Methuselah tree, which makes all the water on Earth, he ended up entombed in salt due to the tree protectors (giant insect-like crab cryptids) causing an earthquake. Years later he breaks out of his imprisonment when the salt crystal gets exposed to water. Anything that he touches with his right hand turns or gets encased in an unbreakable layer of salt, which he uses to almost accidently turn the tree itself into salt. In the end it's revealed his thirst for power has now became a literal, unquenchable thirst, yet unable to touch water to quench it. He demands Zak retrieve the sap from the tree to finally end his suffering. Later he uses a flower from the tree to finally quench his thirst. As it turns out, he became nothing but living salt and drinking the sap from the flower reduced him to a pile of salt, finally ending his suffering.
In Trollz, Zirconia was turned into a tree for 3,000 years. It's a bit more complicated than that, though; at first, she was simply imprisoned within the tree. As time passed, she became part of it. She was conscious the entire time.
Spinell, her husband, was trapped in the form of a dragon. That couldn't talk.
The short film Alma is about a little girl lured into a sinister toy shop by a doll that looks just like her, ending with her becoming the doll after touching it and the shop setting out another doll to lure another victim.
In Gargoyles, the Gargoyles whose bodies composed the Cyborg Coldstone are given a moment of freedom by a spell that allows them to possess the bodies of their living brethren in the clan. Coldstone and his mate briefly contemplate keeping the bodies, but eventually give them back up shortly after it's discovered that the Gargoyles they're possessing are still conscious in their bodies. Fortunately, this was part of Puck and Xanatos' plan to transfer two of their consciousness' into new android bodies, leaving Coldstone in sole control of his own.
Xanatos narrowly avoids this when he acquires a large magical pot which is said to grant "life as long as the mountains" to anyone who bathes in it. Xanatos hesitates to plunge in and Owen offers to test it for him, plunging his fist... and seeing it turn to solid stone.
In the backstory to the series, Nightmare Moon was imprisoned in the moon for a thousand years, and it's implied she was aware the entire time. However, her sanity doesn't seem to have suffered from the experience.
There have been fanfics written that try to describe what her isolation must have been like, especially considering that the reason she turned evil in the first place was because she was lonely. Some of these fics imply that Celestia offered her an early release if she reformed; others aren't so generous.
A later episode confirms Discord, when encased in stone, is able to observe the world around him, which is probably why he was placed in the middle of an empty garden where nothing important happens.
There are also the Windigos, spirits of cold and hatred that feed on hatred. They cause ponies to hate each other and then freeze them alive so they'll have a continuous food source.
King Sombra of season 3, trapped in a glacier for 1000 years while he also cut his kingdom off from the outside world for that long.
In the season 6 finale, the Mane Six, Spike, the Royal Family, Discord and Trixie are all kidnapped by Chrysalis and trapped in cocoons, unable to move around, talk or even speak. The only thing that they can do is move their eyelids and twitch their hooves.
In the original My Little Pony 'n Friends, ponies were at various times turned into glass, turned to stone, and frozen in ice.
After coming back their first experience with the time machine, they bring back a T-Rex which tries to eat Candace only to be hit by Dr. Doofenshmirtz's freeze ray turning it into a living statue. He wanted to use the same ray on Perry the Platypus and other secret agent animals.
The Galaxy Rangers episode "Psychocrypt" demonstrated that after having their soul torn out painfully, those tossed in the device are fully aware of what's happened, their Life Energy is used to make a construct the Queen (the person who put them there) can see and hear through, forced to do her bidding. God Save Us from the Queen!.
Jimmy Two-Shoes: First off, it's implied that the other members of the Heinous family are still conscious in their Human Popsicle state. There's also a throw-away joke about a gnome being completely encased in gold while still conscious.
At the end of the Superman: The Animated Series episode "Action Figures", the android Metallo is left encased in lava underneath a volcano. His Inner Monologue reveals that he is unable to see or hear anything (in addition to the loss of taste, touch, and smell from being a robot in the first place). To keep himself sane, he gives us this chilling thought:
I am Metallo, I am Metallo, I am Metallo...
...but he gets lucky and is rescued by a criminal organization. He angrily describes his experience to Superman in the next episode where he appears, “Heavy Metal”, (the experience obviously having driven him insane and sending him on a Roaring Rampage of Revenge):
Metallo: Do you remember how you left me Superman? Buried in rock? I couldn’t move! I couldn’t see! I couldn’t hear! But I could think. And all I thought about how I was going to make you pay!
Dark Danny's ultimate fate in the Danny Phantom special "The Ultimate Enemy". He's trapped in a Fenton Thermos and exists outside of time, for all eternity. Hopefully.
In Beast Wars, and thus throughout the rest of the Transformers: Generation 1 continuity, it is revealed that Starscream has a mutant, immortal spark. After being killed by Galvatron (again), Starscream spent countless centuries as a disembodied spark, drifting through the cosmos, before finding a way to go back in time, through the same Transwarp time hole that brought the Maximals and Predaconsof Beast Wars into prehistoric Earth. After being defeated here, his spark was once again doomed to wander the cosmos until it could hopefully possess some being.
Near the end of Monster Truck Mater, Tormentor (Mater's monster truck wrestler alter ego) actually traps Paddy O'Concrete (an Irish modified cement mixer monster truck) in his own cement.
South Park gives us unfortunate kindergarten teacher Mrs. Claridge, who is burned so horrifically in an accident caused by the boys in pre-school that she's confined to a mechanical wheelchair, unable to move or speak, except beeping one time for yes, and two times for no (in a direct Shout-Out to Captain Pike from the Star Trek episode "The Menagerie"). This earns her the sympathy of her fellow civilians, but things really go downhill for her when her chair's batteries go dead.
...in the middle of the street, and the townspeople think she's trying to commit suicide.
One wonders how Teen Titans villain Malchior took being imprisoned in that book for a thousand years.
Not to mention that there were superheroes being frozen and held captive by the Brotherhood of Evil during a portion of the final season, and a later addition to this group is Robin.
Upon losing a game, sprites and binomes alike can get "nullified" - in-universe, that means reduced to a deformed, slug-like creature that can't make any noise above a squeak.
Luckily, right at the end of the series, Phong almost perfected a cure. Until Megabyte takes over and the show is cancelled
The Medusa Bug episode, which proceeds to turn everything in Mainframe into stone.
In Mummies Alive!, Scarab murders the son of the Pharaoh in order to obtain immortality; since Pharaoh cannot execute Scarab, he has him entombed instead. The modern-day archaeologist who accidently frees Scarab from his imprisonment many centuries later notes that the walls have multiple tallies scratched into them, caused by Scarab counting out the days of his immortal existence.
This is the terrible fate Van Kleiss suffers in Generator Rex. His attempt to control time misfires when Breach interferes, knocking him through a vortex that sends him all the way back to Egyptian civilzation. In order to get back to the present, he constructs a "hibernation" chamber that uses his Nanites to halt the aging of his body while stayingfullyconscious for4,000 years. Worse, he's forced to recreate the chamber each time it cops out too soon all the way up to the present, painstakingly waiting through era after era for his exodus. If that wasn't bad enough, a spectral entity is chasing him though it's revealed to be a mutated Breach being dragged along each time he sits in dormancy. Eventually, it takes so much of a toll on Van Kleiss, nearly all of his Nanites have died and the isolation drives him to insanity, causing him to forget his own identity and purpose. When he finally makes it back to present day, he manages to recover his sanity little by little after Black Knight meets with him and tells him to get a hold of himself.
In the finale of Action Man, this fate befalls Dr. X, the Big Bad. He's gained superhuman abilities, doesn't need food or air any longer, and becomes Nigh Invulnerable... and then Action Man traps him on an empty rock floating in the immense vastness of space with no means of escape. He actually does scream Action Man's name one last time as the rock drifts away from earth.
In Ben 10: Ultimate Alien "Night of the Living Nightmare" Albedo gets a Cassiopean Dream-eater stuck on his head because he slipped on the spilled smoothie that Ben knocked over in the beginning of that episode. As if having a skull-faced alien jellyfish attached to his head wasn't bad enough, the Dream-eater traps him in a never-ending nightmare so it can feed on the chemicals his fear-addled brain produces. Said nightmare consists of an invincible Ben mercilessly beating him down. He gets better thanks to Galvan medicine, though.
One episode of The Secret Show ends with Doctor Doctor being tricked into sucking the entire universe into the Trousers of Doom! Because she happens to be wearing them, she is forced to float through the void all alone where no one can hear her.
In fact, one could argue that several things, such as the dinosaurs and the Atlanteans, that were sucked into the Trousers of Doom suffered this fate before the universe was added into the mix.
The fate of the Trix at the end of Seasons 1 and 3 of Winx Club. They are trapped in a virtual world full of positive atmosphere that they hate, which is shown to be driving them mad at the beginning of Season 2 before they are rescued by Darkar. Also of note, while the Trix return in Season 5 in most versions, the 4Kids dub ends with Season 3, so in its continuity the three witches presumably remain there for the rest of their lives.
Then there's Valtor/Baltor, who among many unnamed convicts is frozen in the Omega Dimension at the beginning of Season 3 before being released by the Trix. This was intended to last for eternity, and he was awake the entire time he was frozen.
Murderface's grandfather in Metalocalypse. Thunderbolt Murderface (that is his name) has had a massive stroke and was being pulled around in a wagon by his wife who rides a mobility scooter. After his grandmother guilt trips him into it, Murderface buys him his own blink operated wheelchair. Which he uses to say: "I've not had an erection in 30 years" and "I just used my underpants as a restroom" before just saying "Kill me." repeatedly.
Alejandro in Total Drama, after being trapped in the robot suit. Initially, he is able to speak through a communication chip, but it soon breaks, leaving him unable to communicate with anyone for a year.
Scott, the main antagonist from season 4 gets a similar fate. He is paralyzed by Fang and is put in a trauma chair that only let's him communicate via flashing lights for yes or no. What makes it worse is that the rest of player laugh at him and he can't do anything about it.
Codename: Kids Next Door: The Delightful Children from Down the Lane are in reality the permanently Delightfulized Sector Z, who disappeared prior to the series. When they are briefly reverted back to their original forms, they make it all too clear that they are perfectly aware of what has happened to them.
Occasionally, Jack too, especially in "Jack in a Box" and "Oggy's Puzzled".
Steven Universe is surprisingly heavy on the nightmare fuel. This of course starts with Lapis who was imprisoned in a mirror for centuries being used as it's magical power source and could only speak if spoken to, which only Steven did in the episode she was introduced in.
Lapis later fuses with Jasper to form Malachite. Although Jasper intended for this to be a power booster, Lapis uses her power over water to drag them to the bottom of the ocean. Since Lapis can (presumably) end that at any time by unfusing, this trope doesn't apply to her, but rather Jasper, who doesn't seem to be able to unfuse.
Worse then most is what we've seen as the Gem version of "death," having your gem shattered, may be this instead. Gem shards can't communicate but have enough of a "partial consciousness" to be used as power sources, and even the heroes have relatively few qualms about using them as such.
In the episode "Frybo" a gem shard was used to bring life to a creepy french fry mascot costume, and had enough presence of mind to follow orders, albeit too literally leading to the episode's conflict. More gem shards are then used to bring Steven's clothes to life so they could bring Frybo down. In "Secret Team," the gem shards were able to grow mutated limbs and move around the temple, causing chaos.
In the worst instance we see what the losing side of the gem civil war did with shards of fallen Crystal Gems. The losing side buried them in rocks under high pressure to force them to fuse together; some of these shards are combinations of two limbs, two feet, or other appendages, the larger ones are conscious enough to briefly form human silhouettes and scream together in agony before turning into a horrible monster, which was seemingly conscious enough to recognize Garnet and silently reach out for help.
Far, far worse though is The Cluster a massive forced fusion made up of thousands of gem shards, that if it ever takes form will shatter the earth like an egg and kill everyone on it in the process. Even worse is that the new resident expert on gem shards clarifies what exactly they're trying to do. Every shard and forced fusion monster is forming some kind of body, a limb or several depending, because they are all desperately trying to find the rest of there pieces to be whole again. They know what's happened to them and can sense other gems but can't tell what's a part of themselves and what's another gem because of how thoroughly their personalities have been warped by the process of being shattered and/or fused together.
The Wander over Yonder episode "The Wanders" has Wander accidentally getting split into 420 aspects of his personality, leaving the real Wander to just stand there with Blank White Eyes. After Sylvia puts them all back together, Wander seals up the cave and remarks that he'd hate to see anyone else go through what he went through, implying that on some level he was aware that he'd been shattered into fragments of himself and was incomplete and in danger of fading from existence.
Another example of this is seen when Sylvia Unwittingly begins talking to Dominator about having fun. She states that she knows exactly what Sylvia means and begins talking about blowing up a sun so that the inhabitants of the planet that orbit it freeze and are stuck in their agonizing and final positions forever.
This would've been the fate of Raggedy Arthur in the Raggedy AnnChristmas SpecialThe Great Santa Claus Caper. The villain, Alexander Graham Wolf (kind of an Expy of Wile E. Coyote is using a machine to encase Christmas toys in "gloopstik," and at one point, poor Arthur goes through the machine. The poor pooch is completely encased in a block of gloopstik from the neck down. Although he can breathe and bark (although why a rag doll dog would need to breathe goes unexplained), he is incapable of moving under his own power. Alexander claims gloopstik is incapable of being broken, meaning Arthur is effectively stuck this way for all eternity. Fortunately it makes no difference to Raggedy Ann and Raggedy Andy; after getting over their initial horror and anger and defeating the villain, they tell Arthur they'll always love him no matter what, whereupon the gloopstik shatters thanks to The Power of Love.
This would've also been the fate of Alexander G. Wolf himself, since he, too ends up being put through the machine. Like Raggedy Arthur, he winds up encased from the neck down and unlike Arthur this is a good thing since he is a living biological character who needs to breathe and eat. Since the machine had been on its Christmas tree setting, Alexander ends up in a chunk of gloopstik shaped like a Christmas tree, with lights and a star and everything, which allows the special to downplay the true horror his situation: rather than focusing on the fact he'd die a slow, agonizing death from being unable to excrete his own bodily waste, the defeated villain merely bemoans that now he'll have to live his life as a Christmas tree, wailing, "I don't know how to be a Christ-mas tree!" Despite this, it's still rather disturbing seeing the special's bad guy sobbing his eyes out at his predicament, and fortunately for him, Raggedy Ann and Andy agree, as he, too, ends up being saved by The Power of Love.
In Young Justice, Jaime Reyes (Blue Beetle) experiences a taste of this. Not only was he told that in the future, he would betray the human race for The Reach, he eventually succumbs into this prophecy despite his desperate attempts to avoid his fate. Jaime falls under control of the Reach and as a result, he was trapped in his own mind for months, unable to control is body and could only sit back and watch in horror as The Reach pretended to be him, deceived his family, and betrayed his team.
The Dexter's Laboratory episode "Photo Finish" had a villain named Red Eye attempt to use a camera to turn Dexter into a photo of himself. Dexter ends up escaping by deflecting the camera's laser back to Red Eye, turning him into a photograph instead. Red Eye's alarmed reaction seen in the photograph indicates that victims of this transformation are still conscious.
The Buzz Lightyear of Star Command episode "The Shape Stealer" featured a cloak-like organism created by Zurg's R and D that was able to possess people by wrapping itself around them. It is mentioned by two of its victims (a bus driver and Booster) that individuals possessed by the Shape Stealer are still aware of their actions and can't do anything about it.
"Jack and the Lava Monster": the titular creature is a Viking warrior trapped in an unbreakable crystal for eternity by Aku, unable to die a warrior's death and join his comrades in Valhalla.
In the penultimate episode, Ashi is twisted into a demonic version of herself by her father, Aku, and is forced to fight against Jack. She can't break free, and Jack's attacks hurt her just as much as they would hurt Aku, and she is forced to watch as Jack emotionally crumples and surrenders his sword to Aku.