Baneful Reprisal

When another creature hits you with a melee attack, you unleash a  torrent of baleful energies that flood towards the attacker, and the creature must make a Constitution saving throw. On a failed save, it takes 3d6 necrotic damage and has the poisoned condition until the end of its next turn. On a successful save, the creature takes half damage.

At Higher Levels. When you cast this spell with a slot of 2nd level or higher, the damage increases by 1d6 for each spell level above 1st.