The Mouse-Merized Cat(1946)

Babbit hypnotizies Catsello, despite his efforts to resist, into believing he's Bing Crosby, Frank Sinatra, and Jimmy Durante, then a chicken, and finally a dog, who he sics on the cat. The cat hypnotizes him back. Finally, Catstello hypnotizes both of them into cowboy and horse, leaving him alone to enjoy the deli they live in.