Kitty Foiled (1948)

Tom is, of course, chasing Jerry. He's about to administer the coup de grace when a canary intervenes, dropping the bottom of his cage on Tom. Tom then chases the bird a while, and Jerry intervenes at the critical moment. The bird helps Jerry get to his hole. The two continue to team up against Tom. The bird points a gun at Tom and chases him with it; Jerry drops a light bulb, making Tom think he's been shot. They celebrate, but Tom comes to, tying Jerry to the model train tracks. The bird drops a bowling ball, sending Tom crashing into the basement. —Jon Reeves