Scapular of the Ankylosaur

Wondrous item, rare

This thick monastic scapular is dense and weighty, like a heavy leather apron. While wearing it, you have a base AC of 14 + your Dexterity modifier (to a maximum of +2). You can't benefit from wearing other armor while using this AC.

Earthen Slam. While wearing the scapular, you can use an action to stomp the ground beneath you, sending out a shockwave that affects all other creatures within 15 feet of you. Each creature must make a DC 15 Strength saving throw. On a failed save, a creature takes 3d6 bludgeoning damage and 3d6 thunder damage and is knocked prone. On a successful save, a creature takes half as much damage and isn't knocked prone. This property of the scapular can't be used again until the next dawn.

Shield Battery. While wearing the scapular, you can use a bonus action to magically enhance its protection. You gain a +5 bonus to AC until the start of your next turn or until you remove the scapular. For the duration, whenever a creature hits you with a melee attack, that creature takes 5 bludgeoning damage. This property of the scapular can't be used again until the next dawn.

Worn by those protecting the old ways of the world.
The really old ways.