Blood Knife

You draw a small amount of blood from your hand, dealing 1 damage to the caster and use it to form a knife which you hurl at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 piercing damage. If the caster misses with the attack, the blood returns to the caster, and may be used by the caster on the following turn to cast the spell without taking the damage again.

This spell's damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10).