Bloodbath

You cut yourself with a dagger and allow the blood to flow across your body. You take 1d6 necrotic damage when you cast this spell. Each creature within 30 ft. of you must make a Constitution saving throw. Creatures have disadvantage on their saving throw if they are at or below half of their maximum hit points. On a failed save, blood begins to flow from any existing wounds and other openings in the creatures body, causing it to take 2d6 necrotic damage at the start of each of its turns.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage a creature takes on a failed save increases by 1d6 for each spell level above 2nd.