Blood Knife

You create a shard of frozen blood and fling it at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes 1d8 piercing damage. The target and each creature within 5 feet of it must succeed on a Dexterity saving throw or take 1d8 necrotic damage.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, you roll 1d8 for each spell slot above 1st level. The result of the roll reduces your health by that much but increases the damage of the spell by the equivalent amount.