Mauler

Jacob, a former soldier, returns to his childhood mining ghost town to sell the family house. The first night is shattered by a familiar knocking in the basement—the same pattern he heard twenty years ago, right before his sister vanished. The local sheriff just shrugs: "Something always knocks down there." But when Jacob descends, he finds not rusty pipes but a network of tunnels where the echo doesn't repeat sounds; it repeats his family's last words. Now the knocking is following him, mimicking his every footstep with a three-second delay.