Deadly Friend is a 1986 American science fiction horror film directed by Wes Craven, and starring Matthew Laborteaux, Kristy Swanson, Michael Sharrett, Anne Twomey, Richard Marcus, and Anne Ramsey. Its plot follows a teenage computer prodigy who implants a robot's processor into the brain of his teenage neighbor after she is pronounced brain dead; the experiment proves successful, but she swiftly begins a killing spree in their neighborhood. It is based on the 1985 novel Friend by Diana Henstell, which was adapted for the screen by Bruce Joel Rubin.

Originally, the film was a sci-fi thriller without any graphic scenes, with a bigger focus on plot and character development and a dark love story centering on the two main characters, which were not typical aspects of Craven's previous films. After Craven's original cut was shown to a test audience by Warner Bros., the audience criticized the lack of graphic, bloody violence and gore that Craven's other films included. Warner Bros. executive vice president Mark Canton and the film's producers then demanded script re-writes and re-shoots, which included filming gorier death scenes and nightmare sequences, similar to the ones from Craven's previous film, A Nightmare on Elm Street. Due to studio imposed re-shoots and re-editing, the film was drastically altered in post-production, losing much of the original plot and more scenes between characters, while other scenes, including more grisly deaths and a new ending, were added. According to the screen writer, this version was criticized by the studio for containing too much graphic, bloody violence and was cut back for release.In April 2014, an online petition for the release of the original cut was made.