Bowser's Galaxy Reactor is the game
's final level in which Mario
gets to fight Bowser
for the 7th and final Grand Star
. In this final level entitled 'The Fate of the Universe', Mario & Luigi must get past a lot of obstacles in order to reach Bowser to face off in the final battle. In order to get to the level, you need 60 Power Stars
to enter this final face-off.