Estelle Parsons was initially asked to portray the film's killer, Mrs. Voorhees, but eventually declined. Her agent cited that the film was too violent, and did not know what kind of actress would play such a part. Hughes and Moss sent a copy of the script to Betsy Palmer, in hopes that she would accept the part. Palmer could not understand why someone would want her for a part in a horror film, as she had previously starred in films such as "Mister Roberts", "The Angry Man", and "The Tin Star". Palmer only agreed to play the role because she needed to buy a new car, even when she believed the film to "be a piece of shit." Stavrakis subbed for Betsy Palmer as well, which involved Morgan's character being chased through the woods by Mrs. Voorhees, although the audience only sees a pair of legs running after Morgan. Palmer had just arrived in town when those scenes were about to be filmed, and was not in the physical shape necessary to chase Morgan around the woods. Morgan's training as an acrobat assisted her in these scenes, as her character was required to leap out of a moving jeep when she discovers that Mrs. Voorhees does not intend to take her to the camp. Betsy Palmer explains how she developed the character of Mrs. Voorhees: