:::::One thing that works about the Marxes rendition of this oh-so-obvious gag is that Harpo has the axe concealed in his trenchcoat, so it only appears at the right moment. The coat is for him what Felix the Cat's bag of tricks was for the cat, or Snoopy's doghouse was for the dog. Anyone who can pull a steaming cup of coffee, a lighted candle, a complete silverware, a flask, a fish, a flute, etc. out of his coat certainly has plenty of room. Bugs doesn't have any kind of coat except fur, so he has to reach off-screen for his axe. That was a common WB trick - Bugsy would reach offscreen for a mallet, an axe, whatever... the kind of thing which Harpo had in his coat.  ''''