Bowser Jr. Breakdown

Bowser Jr. Breakdown is a boss minigame featured in Mario Party 9.

Introduction
Bowser Jr. will fly down to the stage in his Koopa Clown Car. A larger version of the car, with two clawed arms sticking out of it, will then float down, and Bowser Jr.'s car will link up with the bigger one.

Gameplay
Players try to defeat Bowser Jr. by rolling dice, which increases the number of glowing spaces on the gauge at the top of the screen. Rolling a three or a combined multiple of three (max. 15) will result in the player who rolled and filled the gauge to that point attacking a number of times equal to the number on the gauge divided by three. Each attack will earn the player three points. Once a player attacks Bowser Jr., the gauge will empty.

When Bowser Jr. reaches half his health, three Bowser Jr. spaces will appear on the gauge. If the combined total rolled on the dice block reaches this space, Bowser Jr. will shoot two dice out. If they equal, the car will arm itself with mallets that it will use to squish the player, pounding them a number of times equal to the number rolled; the player will then lose that many points.

Ending
When Bowser Jr. is defeated, his clown car will explode, revealing several Mini Stars.