Veiled Strike

You shroud the weapon used in the spell’s casting in shadows and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack’s normal effects and until the start of your next turn, the target has disadvantage on attacks made against you. 

At 5th level, the melee attack deals an extra 1d4 psychic damage. The damage increases by 1d4 at 11th (2d4) and 17th level (3d4).