Blood Field

You cause a mist of blood to rise in a 30-foot radius sphere centered on yourself. All creatures of your choice that start their turn within the field or enter the field must make a Constitution saving throw. On a failed save, they take 4d6 necrotic damage, and you regain Hit Points equal to half the damage dealt (rounded down). Creatures within the field cannot benefit from being hidden or invisible.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the initial damage increases by 1d6 for each level above 4th.