Mega Man ZX Advent(2007)

In Mega Man ZX Advent, the main characters discover the power of the mysterious "Biometal model A," which on its own has several attacks, but also has a special Megamerge ability which allows the character to transform into one of eight "Pseudoroid" bosses that each have a unique set of abilities. Once a boss is defeated, players can emulate their powers to find hidden routes, discover rare items and aid their battles against more powerful enemies. The title takes full advantage of the Nintendo DS features to enhance the action-packed gameplay and story line of the popular series.