Thru the Mirror (1936)
Mickey has been reading Alice in Wonderland, and falls asleep. He finds himself on the other side of the mirror, where the furniture is alive. He eats a walnut, which makes him briefly larger, then small. He dances around a lot, ultimately doing a major number with a deck of cards. He dances with the queen, making the king jealous. He comes after Mickey with swords, and Mickey defends himself with a sewing needle. Mickey gets the upper hand, and the king calls for reinforcements. Mickey finds himself chased by several decks, which throw their spots at him. He turns on a fan and blows them away, back through the mirror, where his alarm is ringing.