Jeff’s face looks almost human, but not quite. The contrast between the vivid, bloody red of his smile and the dead, matte white of his skin creates a cognitive dissonance. Our brains scream "This is a person," while simultaneously screaming "Something is wrong with their face." That friction generates pure dread.

Today, we have complex psychological thrillers and AAA horror games. But if you close your eyes tonight, and the house creaks, you might still hear a ghostly whisper from a decade ago: "Go to sleep."

And when you open your eyes, for just a split second, you might see the smile.