- Jerry the Bellybutton Elf/Adonis, Lord of Chaos (debut)
- Mr. Horse
- Powdered Toastman
- Muddy Mudskipper
- Mimby (debut)
- Rudolph the Jazzman
- Wilbur Cobb
- The Announcer Salesman
- Sven Höek
- Mrs. Buttloaves
- Haggis MacHaggis
- Shawn & Eugene
- Shaven Yak
- Fire Chief
- Lump Lout
- Loaf Lout
In this episode, Stimpy is shown playing with his belly button, which is somehow making amusing noises when he sticks his finger in it. Ren starts telling him he'll go insane if he continues to make noises with it.
This appears to start to happen, as he is shown putting baking soda and vinegar in his belly button to make it explode like a volcano, and is shown wide awake sharpening pencils with his belly button.
Ren comes in and accidentally gets his finger sharpened from Stimpy's belly button. As Ren leaves, mad, Stimpy becomes obsessed and hears a voice saying he can come inside. This appears to be true, because he actually goes in causing him to pop into a small coin-like belly button, leaving a small part of his body, a.k.a, his belly button. As Stimpy ventures through the psychedelic inside of his belly button, a song plays.
After meeting Jerry the Belly Button Elf, Jerry puts Stimpy to work as his servant. Stimpy makes the lethal mistake of offering Jerry lint loaf. Jerry goes into a fit of rage and, transforming into a giant pork chop monster named Adonis, Lord of Chaos, chases after poor Stimpy, who desperately tries to crawl out of his own bellybutton. Stimpy manages to reach Ren (who's hosting a party and is inviting various people from season 1 & 2), who doesn't understand his pleas for help, but the two end up in the clutches of the monster, and the two make peculiar heartfelt declarations to each other as they head ever closer for certain death. Mimbi eats Stimpy's bellybutton and ends the episode with Mimby giggling.
- When everyone is leaving the party, someone is heard saying "Come on, Barney, let's blow this pop stand" which was a reference to The Flintstones.
- Ren and Stimpy die in this episode, and Adonis gets chewed to his death while eaten.
- In the beginning of the episode, Ren reads a magazine instead of a newspaper.
- Ren and Stimpy affectionately referring to each other as 'pal' and 'buddy' before being eaten by Jerry is a callback to the episode "The Big Shot" where the pair say it to each other after being reunited.
- This is one of the few episodes to include a song, that being "Climb Inside."
- For some reason, the Ghost from "Haunted House" appears in both his human form and in his ghost form, as if they were different people.