|Series||The Grim Adventures of Billy & Mandy|
|Cartoon Network US Premiere||January 27, 2006|
|Paired with||Giant Billy And Mandy All-Out Attack|
Giant Billy And Mandy All-Out Attack
Billy finds a caveman (which is none other than Fred Flintstone from The Flintstones) while trying to dig up the center of the earth so he can live there because the surface is cold. Fred is so overwhelmed by the modern world that he goes berserk and kidnaps the teacher, so it's up to Billy and the gang to save her from him.
- Story by: Maxwell Atoms and Alex Almaguer
- Storyboard by: Alex Almaguer
- Directed by: Shaun Cashman
- Mandy: Well, he's trying anyway.
- Both: (Chewing the Ribs)
- Harold: (Burps)
- Billy: (Growls)
- Barney and Betty Rubble appeared in the credits.
- Fred Flintstone, doesn't speak (except he says his own name while introducing himself to Billy) in this episode but only grumbles and says his famous line, "Yabba Dabba Doo!" (Sometimes “Yabba Dabba!”)
- This is James Arnold Taylor’s first major role as Fred, as his previous roles were in commercials and promos.