Envenom

Choose a willing creature that you can see within range. Until the spell ends, it exudes poisonous energy. It is immune to poison and any harmful poison effects currently affecting the target are suspended for the duration of this spell. One time on each of the target's turns, when the target makes a successful melee or ranged attack, it deals an additional 2d6 poison damage. Additionally, whenever a creature hits the target with a melee attack, the attacker takes 1d6 poison damage.