Blood Boil

You cut yourself with a bone dagger, taking 2d4 piercing damage that can't be reduced in any way. Your blood then evaporates, and you choose a point within 150 feet of yourself, creating a 20-foot radius sphere centered on that point that fills with a burst of blistering, bloody mist. 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 7d10 necrotic damage and is incapacitated until the end of its 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 this spell.

This spell has no effect on constructs or undead.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the necrotic damage increases by 1d10 for each slot level above 5th.