Wally Wackiman would be a good fink for Mike to abuse and bully. With his flexibility, Wally could be forced to crawl down into some of the muckier areas of the dump to retrieve car parts or ski boots. Concealing or editing out the marionette strings might prove to be difficult though.
Some dude called and suggested that I and Wally fill that role. Not sure that I like Wally being considered a "fink" of any kind, nor do I really want him getting covered in muck and garbage. Also, though you're most likely joking, he's not a marionette, thus leaving a lot more than strings to edit out, as I'd be sticking out of him, from both his torso and left arm. I think there is a better Fink candidate out there, yet.
-Zach