Cedric's Shroud of Retribution

After casting this spell, a shroud of darkness forms around your body. For the duration of the spell, any creature that touches or strikes you with an unarmed or melee weapon attack takes necrotic damage equal to 1d4 + your spell-casting ability modifier. 

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the amount of necrotic damage increases by 1d4 for each slot level above 1st.