Intertextuality is taking ideas from other media texts and shaping them to be used in another media text. Psychos famous shower scene is a good example of intertextuality as many films intertextualize with it. There is intertextuality with Psycho and; Succubus, The Stepfather, What Lies Beneath and Fatal Attraction.
Succubus has refers to Psycho with the idea of the victim getting murdered whilst in the shower and also there is no music or sound whilst the victim is showeing apart from the sound of the water, until the killer arrives and murders the victim. However unlike Psycho, the victim in Succubus is male and the killer is female.
The Stepfather refers to Psycho with the idea of the shower curtain being pulled down by an injured person as they fall down, and the fact that it happened in the bathroom shows the intertextuality. Also, a kitchen knife is used in both films
What Lies Beneath refers to Psycho with the idea of the victim being semiconscious in the bathroom. In Psycho the victim has been stabbed so she is semiconscious for a moment before she dies, and in What Lies Beneath the victim has been given a drug that results in her being physically paralyzed, therefore she is semiconscious.
Fatal Attraction refers to Psycho with the use of shadows which add more suspense. A kitchen knife is used in both films and there is also a scene in the bathroom in Fatal Attraction which is a reference to Psycho.