If you are a duck on the make, or a Rascally Rabbit trying to escape the hunters, or just a dog that thinks it's "cute" to wear a turkey costume (or, at least, has an owner who does), you have a good chance of turning into an Ass in A Lion Skin. This involves one animal (usually a Funny Animal) that attempts to pass as an animal of an entirely different species, not simply of a different style or level of reality -- Augie Doggie pretending to be Top Cat, but not Augie Doggie pretending to be Doggie Daddy, Scooby Doo, Underdog, Pluto, or Rin Tin Tin. Note also that the trope specifically excludes an animal dressed as or imitating a human being (or vice versa).