Get to the boss in the level Castle of Big Guy the Stilted (4-8). He takes three blows to kill. For the third blow, stomp on him and stay near his back. While he is dying, you will be shaking strangely. Then, when he drops into the lava, you will fall through him and die in the lava as you see him dying. When asked to restart the level from the middle ring, a strange buzzing tune will play for a little bit. This has so far only been tested with Baby Bowser.
Submitted by: kornyhatemachine