The Bonecrusher is a weapon appearing in Dead Rising 3 and is available through the Chaos Rising DLC.
It is a giant, Biker-themed hammer. It is very powerful as it will smash through most enemies and debris that it hits. Light attack is a strong swing and Heavy attack is a mighty spin and downwards swing towards the ground.
It is available upon defeating Razorface in the Chaos Rising storyline but it can also be accessed through the Weapons Locker in the main game.