Boom Guy

A Boom Guy is a red Shy Guy that balances a Bill Blaster on top of its head. During the events of Mario & Luigi: Partners in Time, Boom Guys patrolled the halls of Prince Bowser's Castle. Upon spotting an intruder, a Boom Guy would fire a Bullet Bill, engaging the intruder in battle. In a fight, a Boom Guy fires Bullet Bills to attack, an attack that can be dodged by jumping. The Boom Guy may also try to fake out its opponent by firing a puff of smoke before he actually attacks. If a Boom Guy is attacked enough times, his cannon will fall off, leaving him defenseless. When this happens, a Boom Guy will start to panic. Without a cannon, a Boom Guy can merely whistle for help. If heard, two Fly Guys will appear and drop another Bill Blaster on the Boom Guy's head, allowing the Boom Guy to resume the fight. If not heard, the Boom Guy will continue to panic.

Stronger versions of Boom Guys called Elite Boom Guys appeared in Gritzy Caves. These enemies were blue in color and attacked the same way, only their Bullet Bills fired much faster.