Martin P Robinson
Biography
Martin P. Robinson is an American puppeteer, best known for his work on Sesame Street, having performed the characters of Telly Monster, Mr. Snuffleupagus, Slimey, Irvine, Buster the Horse, and Shelley the Turtle. He performed the characters Riff the Cat and Clef on Allegra's Window, and was an animatronic puppeteer for Leonardo in Teenage Mutant Ninja Turtles.
Bio from Wikipedia