Mickey Steps Out (movie, 1931)

Mickey heads over to see Minnie, but Pluto won't leave him alone. He gets there and watches through the window, standing on Pluto, while Minnie plays piano. Pluto runs off to chase a cat and leaves Mickey stuck in the window. Minnie has him in, and he dances to her playing. Pluto chases the cat into the house and causes havoc. The chase leads into the piano, where Pluto picks up the player-piano roll as an extended tail, and the destruction continues.