Forehead against the cold window of the last subway car, Sam watched the tunnel lights flicker past. Then something was running alongside the train — sprinting at an unnatural speed, arms swinging rigidly, keeping pace.
He squinted, trying to make it out. The figure answered by leaning closer, its face impossibly still.
Just as the train swept into a dark stretch, a hand flattened against the glass. It left a smear.