Decay is a 2012 British independent horror film written and directed by Luke Thompson (of the University of Manchester), set at the Large Hadron Collider in Switzerland. The movie was created on a budget of $3,225 and was filmed over a period of two years by Thompson and his fellow physicists. The film was released online for free under the Creative Commons CC BY-NC license, shareable and remixable. Decay was premiered on 29 November 2012 and centres on the idea of the Large Hadron Collider transforming scientists into zombies.

Thompson, a physics doctoral student, came up with the idea of the film while he was walking through the maintenance tunnels at CERN and began thinking that it would be a good location for a horror movie. In an interview with Wired, he stated that the film was initially started for fun, but that it was also an opportunity to "do some satirical commentary on various aspects of people’s perceptions of science".