While you may have all gotten used to thinking of Patrick Stewart as our sweet, British grandpa [1], prepare to do an about-face. The X-Men: Days of Future Past actor is back in the tense, horrifying trailer for Green Room, which already made waves at the Sundance Film Festival [2] in January. The film follows a young punk rock band (including Anton Yelchin and Alia Shawkat) who find themselves being held hostage in a secluded venue after accidentally witnessing a terrifying act of violence. The trailer reveals a lot and will no doubt have your stomach in knots by the end of it. Imogen Poots also stars, and you can check out the trailer above.