You scratch yourself with a small dagger. The blood seems to be drawn into the knife, and the runes on its surface glow purple; you take 1d4 necrotic damage (only when casting the spell, not repeated).

Make a ranged spell attack roll on a target within 30ft. On a hit, the target takes 3d8 necrotic damage. Until the spell ends, you can make the attack again on each of your turns as an action. The spell ends if the target moves further than 120ft away, or if it remains out of your sight for one full round.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage to you increases by 1d4, and the damage to the target increases by 1d8, for each slot level above 3rd.