1.The episode of SpongeBob SquarePants where Squidward breaks a time machine and ends up in another dimension where he is entirely alone and has a mental breakdown.
2.The episode of The Magic School Bus where Arnold takes his helmet off in outer space (essentially killing himself) and his head freezes.
3.The episode of Rugrats where Angelica has a nightmare about the new baby her parents said they'd be having and he tries to eat her.
4.The episode of The Powerpuff Girls where they accidentally create a giant sister named Bunny and she ends up exploding at the end after saving the girls.
5.The episode of Invader Zim where Zim goes blind after staring at the sun for too long.
6.The episode of Courage the Cowardly Dog where Muriel's creepy nephew Fred shaves almost all of Courage's hair off.
7.The episode of The Fairly OddParents where Timmy wishes he was never born and sees how much better off everyone would be without him.
8.The episode of Rocko's Modern Life where Heffer chokes on a chicken ribcage and goes to "Heck."
9.The episode of Captain Planet and the Planeteers where Linka's cousin Boris dies of a drug overdose.
10.The episode of Ren & Stimpy where they're trying to sell a horse rubber nipples and he says he doesn't need them, but asks for a rubber walrus protector (for the walrus he is holding captive in his home).
11.The episode of Dexter's Laboratory where he gives himself laser eye surgery and his vision becomes so good that he sees all of his family's imperfections.
12.The episode of Hey Arnold where Chocolate Boy struggles to get over his chocolate addiction.
13.The episode of Courage the Cowardly Dog when he sees this thing in a nightmare.
14.The episode of My Life as a Teenage Robot where Jenny wants to fit in with humans, so her mom makes her an exo-skin, but the skin comes to life and tries to take over her body.
15.The episode of The Powerpuff Girls where they accidentally race into the future and see what Townsville would look like if they weren't there to fight evil. "Him" runs the town and everyone they know has gone insane.
16.The episode of SpongeBob where they think they killed the health inspector (they didn't) and bury him alive.
17.The episode of Invader Zim where he steals and harvests other kids' organs.
18.The episode of CatDog where Cat tries to clean Dog's teeth from the inside while he's sleeping.