Blood Bullet

Make a ranged spell attack against a creature within range. On a hit that creature must make a Constitution saving throw. On a failure the creature takes 2d8 necrotic damage. The targets maximum hit points are reduced by a number equal to the damage, and you regain a number of hit points equal to the damage dealt. On a success the creature takes 2d8 necrotic damage. Its maximum HP returns to normal after it finishes a long rest. You do not regain hit points if the targeted creature was an undead, a plant, or a construct.

When casting this spell out of a slot of 2nd-level or higher, the damage increases by 1d8 for every other slot after 2nd.