Source: The Book of Many Things

Weapon (any weapon that deals bludgeoning damage), very rare

You gain a +2 bonus to attack and damage rolls made with this magic weapon.

This weapon was crafted to destroy structures made of force, such as those created by Forcecage or Wall of Force . Striking a Large or smaller structure of magical force with this weapon automatically shatters that structure. If the target is a Huge or larger structure of force, this weapon shatters a 20-foot-cube portion of it.