A young boy dressed as a zombie (L) startles a participant along the course of the 5K "Panic in the Dark" obstacle run in Lowell, Massachusetts November 1, 2014. Participants wearing headlamps in the dark had to clear physical obstacles as well as navigate their way around volunteers playing the roles of zombies along a 5K course at night. REUTERS/Brian Snyder (UNITED STATES - Tags: SOCIETY)