Choker of Vengeance

Wondrous item, very rare (requires attunement)

This choker made of finely crafted jade contains the visage of a humanoid face that is not amused. While wearing this choker, any creature that successfully attacks you with a critical hit takes 4d6 force damage, or half as much on a DC 15 Constitution saving throw. A creature that fails its save is also blinded until the end of its next turn.