Nick Normal and the Nickmatics

From Muppet Wiki

Nick Normal and the Nickmatics was a rock and roll band on Sesame Street who performed "The Letter N.", as introduced by Nora Nicks, the host of NTV. The lead singer was Nick Normal, whom was performed by Jerry Nelson.

Nick Normal was made from the Green Anything Muppet. The Nickmatics were made from 3 Anything Muppets, Pumpkin, Fat Blue, and Lavender.

While the Nickmatics were just regular Anything Muppet characters, Nick Normal had a bare resemblence to Sid Vicious.