Dragon Quest Heroes: Rocket Slime/Tank Masters

Tank Masters is a bonus mode in Rocket Slime that allows you to fight in staged tank battles against several enemy tanks in a row to earn rare and unique prizes. Unlike normal tank battles, Tank Masters allows you to choose what tank you pilot in the battle, out of all the tanks you've defeated over the course of the game (except the final bosses tank). Tank Masters is unlocked by rescuing Morrie Morrie in Calmigh Bluff.