As a spectator during theater mode of any King of the Hill match, highlight your avatar and press the 3 button for the Avatar Move menu. Enter these codes for secret moves.

DOWN, DOWN, 2 - "I'm Not Worthy".
DOWN, DOWN, DOWN, 4 - Sleep.
DOWN, DOWN, DOWN, UP, 3 - Throw Tomato.
DOWN, DOWN, UP, UP, 1 - Lighter.
DOWN, UP, 1 - Devil Horns.
DOWN, UP, 2 - Finger Point.
DOWN, UP, DOWN, 3 - "HA!".
LEFT, LEFT, RIGHT, RIGHT, 1 - Raiden Pose.
LEFT, RIGHT, 1 - "FIGHT!.
LEFT, RIGHT, 3 - Shake Head.
LEFT, RIGHT, 4 - Cover Face.
LEFT, RIGHT, LEFT, RIGHT, 2 - "Finish Him!".
LEFT, UP, DOWN, 4 - Cheese.
RIGHT, LEFT, 4 - Stink Wave.
RIGHT, RIGHT, 1 - Point.
RIGHT, RIGHT, RIGHT, LEFT, 2 - Gather Ice.
RIGHT, UP, 2 - Big Clap.
UP, DOWN, 2 - Double Devil Horns Towards Screen.
UP, DOWN, DOWN, 4 - Skunk (Stench).
UP, UP, 1 - Hop.
UP, UP, 4 - "$%#&!".
UP, UP, RIGHT, RIGHT, 1 - "Fatality".
UPUP, DOWN, LEFT, 2 - Diamond.