Wrong Again (1929)

Stable hands Stan and Ollie are tending a thoroughbred named "Blue Boy." But when they overhear two men talking about a $5000 reward for the return of the stolen "Blue Boy," they miss the part about it being the painting, not the horse. They take the horse to the owner's house to claim the reward. The owner instructs them to put "Blue Boy" on the piano and Ollie explains, "these millionaires are peculiar."