Mickey's Mechanical Man (1933)

Mickey has built a robot to compete in the boxing ring against the giant gorilla, the Kongo Killer. Whenever it hears Minnie's car horn, it goes crazy and starts punching any picture of Killer that it sees, even if it's on a brick wall, thus hurting itself. Mickey manages to barely patch his robot together to take on Killer, but after some early success, it gets pummeled by the ape. Minnie fetches the car horn, which brings it back, and it trounces Killer, then flies apart.