Black Mirror

You stand before a mirror, as your ritualists chant around you. Once this spell is cast, a chill passes through your body and your shadow doubles in size. You gain the ability to engulf yourself in your own shadow. When you do this, you become invisible for 1 minute, and gain resistance to all damage except for Force, Psychic, and Radiant. This ends early if you cast a spell, make an attack roll, or force another creature to make a saving throw. This ability can only be used once.