Night of the Mannequins by Tor Nightfire

We thought we'd play a fun prank on her, and now most of us are dead. One last laugh for the summer as it winds down. One last prank just to scare a friend. Bringing a mannequin into a theater is just some harmless fun, right?Until it wakes up. Until it starts killing. Luckily, Sawyer has a plan. He’ll be a hero. He'll save everyone to the best of his ability. He'll kill as many people as he needs to so he can save the day.That's the thing about heroes—sometimes you have to become a monster first.