At the title screen, hold L + R and press X(2), Right, X(2), Down, X(2), Left, X(2), Up. Release L + R and if you entered the code correctly, you will hear a sound. Choose any boarder at the character selection screen and he or she will be replaced by Mix Master Mike on the course, with the ubers of the character that was originally selected. He has decks on his back and a vinyl board. Repeat the code to disable its effect.