Mace of Smiting

You gain a +1 bonus to attack and damage rolls made with this magic weapon, which increases to +3 when used to attack a construct.

When you use this weapon to make an attack and roll a natural 20, it deals an extra 2d6 bludgeoning damage, which increases to 4d6 against construct. When this weapon reduces a construct to 25 or fewer hit points, the creature is destroyed