In the game’s "Freak Show" level, the player enters the "Museum of the Slightly Curious", which features odd antiques like "Salty Jack" (a reference to the mascot for the snack food Cracker Jack) and the "Horse With No Mane" (a pun referencing the 1971 song "A Horse with No Name" by folk rock band America). One of these antiques on display right below a health power-up is a caveman "Frozen in Time!".

The cartoonish, one-eyed Caveman is actually the titular enemy character from the 1991 Midway arcade game Trog. The inclusion was a reference to CarnEvil's Director and Lead Designer Jack E. Haeger also serving as the artist for Trog.