Blood Boil

You choose a point within range, and a 20ft radius sphere centered on that point fills with a burst of searing, blood-red most.

Each creature of your choice that you can see in that area must make a constitution saving throw. On a failed save, a creature takes 8d10 necrotic damage and is incapacitated until the end of it's next turn. On a success, a creature takes half as much damage and isn't incapacitated. A creature dies if reduced to 0 hit points by the necrotic damage.

This is a Sanguimancy Spell.

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, you deal 2d10 additional necrotic damage for each slot level above 7th.