Bowser's Block Party is a boss minigame from Mario Party DS. In it, players fight Bowser after he uses his Mega Morph Belt to become Blockhead Bowser.
First, he turns into a top and spins around the arena, shooting fire from the Golden Bowser Block. After a while, he gets covered in fire. Eventually, he stops and falls over. The player then punches or kicks the Golden Bowser Block five times to defeat that form and turn him into his next form.
In his next form, he becomes a large block and moves like a Tox Box. After moving, he shoots fire from Bowser Tiles on his side. The player must hit the Golden Bowser Block five times when it comes to the ground.
In his last form, he becomes a catterpillar-like thing, with the normal Bowser Blocks as body and the Golden Bowser Block as head. It moves around the outside and the Bowser Blocks shoot fire. The Golden Bowser Block is at first covered in fire. When it stops, it shoots fire from its side, and stays uncovered for a moment. At that time, the player must punch or kick it five times.
When Bowser is defeated, the player beats Story Mode and unlocks Triangle Twisters.