From The Shadows

Somewhere in the deepest tunnel of the dead megacity, the shadow stopped being a shadow. It had been feeding on the last functioning power grid, drinking the current through severed cables, learning the city's language through its dying nervous system. When the grid finally collapsed, the thing peeled itself off the wall and stood up. It had no face - only the shape of a face burned into the air by old neon, a pair of glowing scars where eyes should have been. The scavengers who had been living in the tunnels below never heard it move. They only noticed the temperature drop, then the silence, then nothing. It did not hunt for food or revenge. It hunted because the code baked into its bones told it to, and the code was older than the city, older than the war that killed it, older than the first signal that had crawled out of the dark and called itself alive.