Quaking Mace

Weapon (mace), very rare (requires attunement)

The head of this steel mace is constructed from nine flanges while the shaft is engraved with a scrolling knot pattern. You gain a +2 bonus to attack and damage rolls made with this magic weapon and when you hit, the target takes an extra 2d6 thunder damage. While holding this mace, you have resistance to thunder damage and you cannot be knocked prone.

As an action, you can strike the ground with the mace and cause a small seismic disturbance. All creatures on the ground within 30 feet of you must make a successful DC 17 Dexterity saving throw or be knocked prone and stunned until the start of your next turn. Once you have used this property, you cannot use it again until the following dawn.