Blood Bullet

By opening a wound upon yourself you will a concentrated bead of it to strike a foe. You take 1d4 Piercing Damage. Make a ranged spell attack against the target with a bonus to hit equal to the amount of damage inflicted upon yourself. On a hit, the target takes 1d12 Necrotic Damage.

If you are suffering from a disease or blood bound effect, the target must also make a save against it. 

The damage you take from casting this spell cannot be prevented. 

This spell's damage increases by 1d12 when you reach 5th level (2d12), 11th level (3d12), and 17th level (4d12).