For the scenes where the entity assaults Carla Moran at night touching her breast while she is sleeping, the visual effects team designed a prosthetic breastplate and full body that could be "indented" from below pretending fingers that "touch" her body.
The real-life Carla Moran's teenage son described a particularly vicious attack in which Carla was thrown by the malevolent force and hit her head. He tried to intervene, but he was also thrown, breaking his arm. In the filming of the movie, the actor playing the son broke his arm in that scene, and the curtains tore from top to bottom without explanation.
Barbara Hershey said, "I resent being put in the position of defending the film. We worked really hard not to make it exploitative. Rape is one of the ugliest, if not the ugliest thing, that can happen to someone. It's murder of a sort. I have no answer for those who are offended. They're right, but I don't think our intention was to exploit the subject, or the result. Truly, I don't. I think we did well with it." When Hershey was interviewed for the Scream Factory Blu-ray of The Entity in 2018, she had nothing but kind words to say about director Sidney J. Furie, even saying that going to work on it was fun and stress-free because he was at the helm, making her feel comfortable, safe, and protected at every turn. She also described it as one of the best creative experiences of her career.
Actresses Jane Fonda, Jill Clayburgh, Bette Midler and Sally Field were initially sought for the role played by Barbara Hershey.