Bloodrend

You draw out a portion of your blood, sacrificing up to 20 hit points, and target a point within range. Each creature in a 15-foot-radius sphere centered on that point watches in horror as their blood painfully exits their body through thousands of tiny pores and must make a Constitution saving throw. A target takes 6d6 necrotic damage + the amount of hit points spent in the casting of this spell on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 and the amount of hit points you can sacrifice increases by 5 for each slot level above 3rd.