From Wikipedia, the free encyclopedia. Bill Barretta has been performing with the Muppets since 1991, when he performed the body of family father Earl Sinclair on Dinosaurs. He later developed several new characters on Muppets Tonight, including Pepe the King Prawn, Johnny Fiama and Bobo the Bear. Along with having his own Muppet characters, Bill has taken over several of Jim Henson's roles, such as Dr. Teeth, Rowlf the Dog, Mahna Mahna and Swedish Chef, and briefly took over Jerry Nelson's ro...