Martin P. Robinson (born March 9, 1954) is an American puppeteer, who works for the Jim Henson Company. He built, designed, and performed the Audrey II puppets for Little Shop of Horrors. He is also best known for his work on Sesame Street, having performed the characters of Telly Monster, Mrs. Grouch (Oscar the Grouch's mother), Slimey the Worm, Mr. Snuffleupagus, Oscar's niece Irvine, and Shelley the Turtle on the show for over 30 years. He also performed the characters Riff the Cat and Clef the dad on Allegra's Window, and was an animatronic puppeteer for Leonardo in Teenage Mutant Ninja Turtles. He is the puppeteer responsible for training the puppeteers on Sesame Tree. He also voiced the Cat in the Hat in the second season of The Wubbulous World of Dr. Seuss.