The Rock Lobsters

From Muppet Wiki

The Rock Lobsters were a crustacean band appearing in Muppets Tonight Episode 204. They were booked on the show to perform the B-52's song that shares their name, but they secretly planned to seize control of the broadcast, as representatives of the Crustacean Liberation Army. They are eventually foiled by Pierce Brosnan and his flying clocks.

The leader of the Rock Lobsters was performed by Jerry Nelson (speaking) and Steve Whitmire (singing vocals).