SCP-5031 is a non-sapient quasi-humanoid creature of unknown origin (Object Class: Keter). When observed directly it temporarily ceases to exist until the viewer looks away, though traces — scratch marks, blood trails — persist. It cannot be captured on photo or video, yet its shadow does not vanish, so its build can be inferred from the silhouette: an abnormally small head, elbows that branch into three sets of arms, a torso reaching 1.9 meters, the body levitating at a fixed height of half a meter.
It needs no nourishment yet hunts and consumes any human or animal, never sleeps, and shows no expression. But across a series of contact tests its motor and cognitive skills — rolling a ball back and forth, operating labeled symbols — improve rapidly, showing that a thing classed as non-sapient is learning. The file itself is flagged “under review,” so its true nature stays sealed, doubling the horror of a thing that observation erases.