The Grim Adventures of Billy and Mandy (2001)

S6E6 Modern Primitives

While excavating his front yard, Billy uncovers a frozen caveman, whom he dubs Jake Steele, but is actually Fred Flintstone from The Flintstones. Billy attempts to help Fred adjust to contemporary life, but it proves challenging. During a school visit, Fred creates chaos by kidnapping Miss Butterbean and speeding away in Principal Goodvibes' vehicle. The wild pursuit ends with Fred crashing into an ice cream truck, causing him to freeze once more. Instead of retrieving him, Billy opts to bury Fred again. The episode concludes with a glimpse into the future, where both Billy and Fred are thawed by brain-eating aliens.