Boulderhead Mace

The head of this +1 heavy mace is made from a single piece of roughly spherical granite. Once per day the wielder can command the mace to release this head, which grows to the size of a Large boulder and rolls quickly in a direction the wielder specifies. The boulder rolls in a straight line up to 60 feet, trampling everything in its path for 3d8+5 damage (Reflex half DC 19). The boulder collapses into rubble and dust at the end of its path or if it encounters an obstacle it cannot break through or roll over, creating a 10-foot-square area of difficult terrain. A new stone mace-head grows on the weapon's haft over the next 24 hours, and it is unusable as a weapon until the head regrows.