Blood Boil

Your magic penetrates the body of a creature within range, attacking it from within. The affected creature must make a Constitution saving throw. On a failure the creature takes 5d6 necrotic damage, and has disadvantage on ability checks and attackrolls until the end of its next turn. On a success the creature takes half damage, but is otherwise unaffected.

When you cast this spell using a spellslot of 4th level or higher, the damage increases by 1d6 for every spellslot above 3rd.