Someone's Knocking at the Door

Ray Harris, a med student, sits in his dorm, watching stag films and shooting what at first appears to be heroin but is later revealed to be an experimental drug called "Taldon". He hears a knock on his door and answers it. He is greeted with the sight of a fully nude woman, who makes sexual advances towards him. He reciprocates, only for the woman to metamorphose into a grotesque man with a freakishly large penis. The man attacks Ray, and it is strongly implied (and later confirmed) that the man rapes and kills him.