Hi Trollheart and welcome to MC. Actually, based on your description of the sketch, I'd have to disagree with Kyle's suggestion. It's a good guess, but going by your description, I'd say you're thinking more of the sketch with the Merdlidops from the Dom DeLouise TMS episode.
Dom plays the role of an astronaut who's just arrived on the surface of Planet Koozbane. The Merdlidops pop out of their holes with a systematic steam whistle and cry "Merdlidop!" before going back down. Intrigued by the critters, Dom sets about to investigate the matter. These aliens have fun with him, steaming him, and even stealing his watch. When Dom attempts to retrieve his timepiece, he gets grabbed himself when grabbing one of the Merdlidops, to the point he gets sucked down the hole and becomes another member of the workcrew, his head emerging from one of the craters instead.
This episode is part of Season 2 and will be included in the TMS Season 2 DVD box set released later this year in August.
Additionally, Palisades Toys (makers of the great Muppets line of action figures) released a figure of Koozbane Kermit, Kermit in his reporter's trenchcoat only. This figure included a Planet Koozbane base with two Merdlidops sculpted and painted as part of the set, as non-removable non-articulated PVC figures.
Hope this helps and have fun exploring the rest of the forums.