 SCP-17 is contained in an acrylic glass cage. Attached to the walls, ceiling, and floor of the room, our high-intensity arc lamp spotlights pointed directly at the acrylic cage to ensure that SCP-17 is constantly exposed to light from every angle. SCP-17 is a humanoid figure, SCP-17 seems to be composed of a shadowy, smoke-like shroud. No attempt to find any object beneath the shroud has been successful, but the possibility has not been ruled out. SCP-17's reaction to shadows cast upon it is immediate and swift. SCP-17 leaps at the object casting the shadow and completely encloses it in its shroud, where upon it returns to its normal size, leaving no trace of the object behind.