Bakugan: Defenders of the Core

Cannot be missed. This trophy unlocks upon winning the final story battle. You are forced to use Maxus Dragonoid for this battle. If you have the core energy to spare, it will help to give him combo boost and combo max.

After a little bit into the battle, the game tells you an indirect way to kill the final boss. You have to do it this way. If you attack the boss, his life will keep refilling to maximum. Once you cut the boss's source of power, his invincibility will go away.