My very first idea… ok, so here goes:
SCP-Whatever#, a 7-8 feet tall humanoid. Body structure is similar to a normal human, except for the arms and head. The arms are extra long, so if it's standing up normally the hands would be a few inches from touching the ground. The mouth/jaw opens three or four times wider than a human, eyes are white, and there is no hair on the body except a dirty mat of black hair on the top of its head. Overall, a very skinny and pale body with virtually no muscle mass. No higher brain functions, totally docile, and pretty much unresponsive to stimuli.
Now, whenever someone looks at an exact likeness of its face, whether it be face-to-face, video surveillance, a video copy, or even a photo, at any place in the world, the creature flips. It'll cover its face with one hand and start screaming, sobbing, babbling incoherently, and begin running to whoever saw its face.
Absolutely nothing will stop it at this point.
The viewer could be on the other side of the planet, inside a bunker, under the ocean, it won't matter. The creature will rip through any material and shrug off any and all damage to it to get to the viewer. When it finally gets there, it will kill the viewer. Afterwards, it will sit and scream, babble, whatever for a few minutes until becoming docile once again. It will then try to make its way back to the mountains/wilderness of its natural habitat, where any wounds it received will eventually heal.
That's the idea in a nutshell, of course there will be a bunch of little details in the actual file should it be accepted.
So what do you guys think?