Defend Your Planet!

From Muppet Wiki

An idea for a Henson produced game show called Defend Your Planet! (also cited as Attention Earthlings: Defend Your Planet!) was mentioned a few times by Henson officials and appeared on Henson.com's Featured Creature section. The concept consisted of human contestants facing off against humorous puppet aliens to win in a battle of wits and strengths to save the Earth (and win prizes). The initial concept was developed in 1996 and an alien game show host and his sidekick (both designed by Ed Eyth) were later built. A pilot episode of the children's game show was produced; however, the pilot did not sell and the show never went into production.

Concept sketches include a character with an exposed brain, a feature which would later be seen in the character design for Craniac.