A heady surprise is the act of being woken from a dead sleep to find a towel on you and a creep jerking off on you, and telling you to go back to sleep he will be finished soon.
When a guy's fat gut is so huge it resembles a hippopotamus head ... it therefore must be a hippopotamus that only has 2 legs and has purchased itself a lovely man's head for a hat (probably not such a lovely hat given the size of the gut)