The smallest Muppet, Slimey Worm is Oscar the Grouch's pet earthworm. Though Oscar is the only one who can communicate with Slimey, this doesn't stop the little orange-and-red striped fellow from getting into all sorts of adventures on Sesame Street.

In 1997, to celebrate the show's 25th anniversary, it teamed up with NASA and ran a 19-episode story arc where Slimey, an international team of worms and a stowaway chicken went to the moon to test the quality of moon dirt to play in relative to that of the Earth.