Blood Boil

You choose a point within 120 feet of yourself, and a 20-foot radius sphere of searing blood red mist fills the area. Each creature in that area must make a constitution saving throw. On a failed save, a creature takes 12d8 necrotic damage and is incapacitated until the end of its next turn. If a creature starts its turn in the mist it must make the saving throw again. On a success, a creature takes half as much damage and isn't incapacitated. If a creature is reduced to 0 hit points while in the mist, it explodes in a burst of boiling blood and viscera in a 10 foot radius sphere. All creatures in this area must make a dexterity saving throw taking 5d6 fire damage or half as much on a success. This spell has no effect on undead or constructs.

When using a spell level of 9th or higher, the damage increases by 1d10 necrotic damage and the area of effect increases by 10 feet per spell level above 8th.