Several American cinema chains have banned audience members from wearing masks to screenings of the new "Joker" film.
There've been concerns from the families of victims of a mass shooting in 2012 during a showing of "The Dark Knight" in Colorado.
Representatives from the group say that the upcoming movie starring Joaquin Phoenix is "like a slap in the face."
They're worried about the new film - which tells the story of a mocked stand-up comedian turning to violence.
Sandy Phillips daughter Jessica was killed in the Aurora Theatre shooting.
Sandy fears that one person may be out there who is on the edge, "who is wanting to be a mass shooter, maybe encouraged by this movie. "
Landmark Theatres which has 52 cinemas across the United States says "We Want All Our Guests to Enjoy The Joker for the Cinematic Achievement That It Is. But No Masks, Painted Faces or Costumes Will Be Permitted into our Theatres. Thank you!"