He is a small green frilled lizard, who frequently gets his frill stuck in things. He is very fast, hyperactive, a bit of a motor-mouth and a coward, though he does try to help and shows some guts when he ends up on Joanna's back and pulls a cowboy act with her.
Frank is terrified of being killed and turned into a purse. He is also extremely cowardly and hyperactive.
Frank is first seen after Cody is thrown into a cage with him by McLeach. Frank is one of the many animals that McLeach has poached for various ways of making money. He quickly joins in Cody's yelled defiances of McLeach, though he becomes frightened at first when approached by the boy. After Cody tells McLeach he'll never tell him where Marahute is, Frank pops out of the hay and tells McLeach where the mother eagle is. Cody then asks Frank where he came from, and he says he was from the desert. Frank covers his ears when he hears Krebbs tell him he is going to be made into a purse. Cody then tells Frank they're going to get out of here. Frank uses his tail to pick the lock on the cage and frees himself. He then hatches a plan to get the key. After successfully retrieving the key, while making a boisterous racket, he gets caught by McLeach and shuts himself back in the cage out of fear. He isn't seen again for the rest of the film.