Tainted Blood

You extend your hand toward a creature you can see within range and direct the essence of death into their veins. The creature must succeed on a Wisdom saving throw or take 1d10 necrotic damage. 

The blood of any creature targeted with this spell will turn black for 1d10 rounds. All healing targeted at the creature is halved for the duration.

At higher levels, this spell's damage increases by 1d10 when you reach 5th level (2d12), 11th level (3d12), and 17th level (4d12).