Rudy the Clown is the final boss in Wario Land 3. After collecting all 5 Music Boxes for the Mysterious Figure in the Temple, they revive his power and the figure's true form is revealed to be Rudy, a giant clown who is trying to dominate the world.
To defeat Rudy, the player has to jump on his fists as he tries to punch them, and then throw the fist back at his face, and make sure not to get caught by the hands when they try to grab him, else its game over. Rudy is the only boss in Wario Land 3 which you can actually get a Game Over screen on.
Rudy also appears in Dr. Mario 64 as a boss character.