Mace of Crushing

The Mace of Crushing is a +3 footman's mace of black metal with gold decorations on the hilt. On a natural 17 or better, it has one of two effects. Against an opponent wearing armor, they take normal damage, but their armor is damaged and loses three steps of protection (magic armor gets a saving throw with its bonus, non-magical light armor like leather is effectively destroyed). If the target is unarmored, they take double rolled damage. On a natural 20, an unarmored target takes double maximum damage.