Amulet of Vicious Resentment

Used as a reaction.
Upon an enemy attacking the wearer within a range of 60 feet, the wearer can mark the enemy with a Grudge.
Upon subsequent rounds, as a bonus action, the wearer can damage the target for 1d4 phycological damage. 
Lasts 1 minute.

Notes: Damage: Psychic, Damage, Buff, Jewelry