SCP-096 is a tall, emaciated humanoid that normally sits curled in its cell, harming no one. But the instant anyone sees its face — in person, in a photograph, or on video — it enters a violent fit and races, at an unstoppable speed, to wherever the viewer is on Earth, kills them, and then falls quiet again.
The heart of the horror is the taboo that the act of seeing itself becomes a death sentence. Fleeing and hiding are useless, and there is no way to undo having looked. Because observation alone seals one’s fate, it is a textbook case of horror in which the gaze is both the seal and the curse.