Watch I'm a Monkey's Uncle for Free: How to Stream the Movie Online at 123Movies. . Set in the stone age, the stooges are cavemen who must have various misadventures hunting, gathering, and otherwise coping with prehistoric life. When some other cavemen threaten to take their women ("Aggie", "Maggie", and "Baggy"), the boys fight them off with a catapulting tree branch that shoots rocks and eggs.