Aura of Consumption

You surround yourself in a field of necrotic magic that drains the life force of whoever enters it. A creature that starts its turn within 15 feet of you or enters the aura for the first time on its turn must make a Constitution saving throw. On a failed save, it takes 2d8 necrotic damage and can’t regain hit points until the end of its next turn.

When a creature with a hit point maximum of 20 or more is killed by your aura, you can use your reaction to regain 3d8 hit points.