Uncanny Valley is a term that is used for the emotional response as an object increases in resemblance to being human. As an object gets closer to looking human, the imperfect object provokes feelings of unease or revulsion in the people present. This dip is the valley and the feeling is uncanny. This uncanny valley is an evolved trait in humans. It is not fully understood.

It is here I, John Stone of the Human Evolution Project, have figured out the truth.

One of the most frightening things I’ve ever heard was when one of my friends, a fellow scientist at the Project and operational commander of the division, pointed out the existence of the uncanny valley implied that at some point there was an evolutionary reason to be afraid of something that looked human but wasn’t.

In the past, humans were not the only hominids. Homo Sapiens have been around for a few million years. We shared Africa’s forests and savannas with upwards of two dozen different hominid species, all ranging from being about as intelligent as a lemur to a few that were on par with us.

This uncanny valley thus makes sense. As we were not the only “humans” on Earth, it was paramount to be able to discern who was actually of our species from several different species. It was useful to be able to figure out who you were capable of producing offspring with, as those who were not of our species would produce sterile or disabled offspring. All that effort into socializing, producing, and raising your infant only to find out it would not last and produce healthy adults to further the species would be wasted. Waste is bad.

But all of them have died out for one reason or another. We’re the only ones left.

Really, we’re the only ones left. Have been for at least two hundred thousand years. There’s no boogeyman hominid species lurking around the corner in our society. So why does uncanny valley still exist? Why do we still shudder when viewing things that look almost like us, but are not us?

We shouldn’t be afraid of anything. Sure, humans lack the strength, endurance, or power that other creatures have. Bears significantly outrank us on all three of these ratings. But as a species, we’re not afraid of bears. Why do we have an uncanny valley that terrifies us to our core? What could actually instill a species-wide fear?

With my fellow scientists at the Project, we have finally figured out the answer. Pouring over a century of data, decades of video surveillance, and even communicating with neighboring interstellar civilizations, we have come to the conclusion that the answer is that we are not the top of the food chain as we have come to believe.

Out there is a species of shapeshifting predators that hunts only the top level of intelligence in its ecosystem. Piecing together the puzzle across several entire civilizations have come to the conclusion that this is an incredibly ancient species. They have been here before any of us even thought about building the first civilization, before we were hunter-gatherer tribes, even before primates were actually a thing. Not monkeys. Primates.

The same for the other civilizations. A shapeshifting predator that exclusively hunted the people that built civilization and no more. It didn’t bother going after any lesser creatures; their equivalent to dogs, deer, or fish. It preyed specifically on what we’d all call people. It was a people hunter.

This species hunts by shapeshifting into something that resembled people but wasn’t fully person-looking. It would try to gain our trust and come into our homes. Then in the privacy behind the walls, it would eviscerate us and consume our remains, paying particular attention to whatever was the brain of the person’s species. It would then stage the scene as if a murder or accident occurred, whichever was more believable, before slinking off into the darkness to digest, grow, and rest. It would later come back to hunt again.

This is where the uncanny valley came from. A biological response to being preyed on by a predator that we couldn’t fully explain or describe. All we knew was to not trust anything that didn’t look like us. Once you cannot trust someone, you are open to destroying them in any way possible. The more horrific, the better. From spear stabs to gas chambers to nuclear weapons, you did what you had to do to destroy them.