Amulet of Rot
Wondrous Item (Amulet), Very Rare, Requires Attunement by Bard, Cleric, Druid, Sorcerer, Wizard, Warlock
An amulet that appears to be some kind of bone carved into the shape of a skull, with two glowing eyes, one green and one black. Select one creature within 30 feet. The creature must be able to see into the eyes of the amulet. That creature must succeed a CON Save DC = 8+Proficiency+Your spellcasting modifier.
This action deals 3d8 Poison and 3d8 Necrotic and reduces the creature MAX HP by the amount of damage dealt the creature reverts back to normal MAX HP after a long rest. Or half as much on a pass with no HP changes. The amulet starts with 5 charges. Once it reaches 0 charges it regains 1d4+1 charges over a short rest. Every time it hits 0 charges roll a d20 on 1 the amulet turns to dead matter of an unknown source and is unusable.