Based on the search results, it is not possible to determine what the Regal mystery movie was tonight. The Regal Mystery Movie Monday is a program where moviegoers can see a new release before it opens to the public for just $5, but the movie title is not revealed until the screening. The program is available at select theaters, and the movie shown may vary by location and date. Therefore, it is recommended to check with the local Regal theater for information on the next Mystery Movie Monday screening.