Blood Amulet
Source: Arcana Unleashed
Wondrous Item, Rare (Requires Attunement)
This delicate amulet looks like a diminutive beating heart impaled with spikes. It has 3 charges and regains 1d3 charges daily at dawn.
Whenever you deal damage to a creature, you can expend 1 charge to deal an extra 2d10 Necrotic damage to the target and force it to make a DC 15 Constitution saving throw. On a failed save, the target gains 1 Exhaustion level.