Yes, there was an episode featuring a "Dave Goelz" Muppet. He was a guest on the show, and explained the life of a human (along with some footage of the real Dave with his family). Bill Baretta played him (since Dave was playing Stinky), and had a lot of fun with him. He gave him a sort of hysterical laugh, and did a sort of "Ee-yahh!" noise and shook his fists out. Very strange.