Blood Bolt

The caster slices open the palm of one of their hands and mutters infernal words as the veins on the cut hand and arm go black before a bolt off crimson/black blood launches out of the casters hand and into the target where it absorbs into their skin and attacks their blood vessels from within. On casting the caster takes 1(d10) necrotic damage. On a hit the target takes 4(d10) necrotic damage and must succeed a Constitution saving throw or become poisoned.