Catherine Tramell

Basic Instinct establishes Tramell as a beautiful wealthy heiress and successful crime novelist who is connected to the violent stabbing death of a washed up rock musician, Johnny Boz, who was found in his bed tied to the bed posts with a white silk scarf. She is subsequently investigated by San Francisco homicide detectives Nick Curran (Michael Douglas) and Gus Moran (George Dzundza), who learn that Boz died in exactly the same manner as a character in Tramell's most recent novel. Tramell shows little emotion upon hearing of Boz's death and, under questioning by the police, behaves provocatively; in the film's most famous scene, Tramell re-crosses her legs to show that she is not wearing underwear beneath her short skirt.

Curran looks into Tramell's troubled history and links her to the deaths of her wealthy parents (who died in a boating accident), her counselor at UC Berkeley (who was also killed with an ice pick in an unsolved homicide), and her former fiancé, a famous boxer. She also has a habit of befriending imprisoned murderers such as her girlfriend Roxy, who killed her brothers as a teenager, and Hazel Dobkins, an elderly woman who killed her husband and children for no apparent reason. However, when he confronts Tramell, she taunts him with knowledge of his drug addiction and his killing of two tourists on assignment while high on cocaine. Thinking that Tramell received the confidential information from an adversarial Internal Affairs investigator, Marty Nilsen, a violent Curran gets himself suspended and falls into a drunken stupor. After Nilsen is found dead, he becomes the prime suspect. Curran, increasingly seduced by Tramell, becomes sexually involved with her; she tells him that he will be the basis of the character in her next novel.

A torrid affair between Tramell and Curran begins with the air of a cat-and-mouse game. Curran shows up at a club and witnesses her sniffing cocaine in a bathroom stall. Later, they have aggressive sex at Tramell's apartment.

Roxy, jealous of Nick's relationship with Catherine, unsuccessfully attempts to kill Curran and dies in a car crash. Tramell's apparent grief over Roxy's death leads Curran to doubt her guilt. Curran then learns that as a college student, Tramell had a lesbian encounter with Beth Garner, a police psychologist he previously had an affair with. Upon finding the manuscript to Tramell's latest novel, and reading the final pages where the fictional detective finds his partner's dead body, Curran realizes that Moran is in danger; he is too late to stop Moran's apparent murder by Garner, whom he shoots when he thinks she is retrieving a weapon. Evidence collected in Garner's apartment points to her as the killer of Boz, Nilsen, Moran, and her own husband. She is ultimately branded as the killer.

Curran is left confused and dejected, knowing from the manuscript that Tramell was involved in Moran's murder and somehow framed Garner, but tells no one. When he tries to confront her after returning to his apartment, the two end up making love. During a session of pillow talk where they discuss their future, Tramell reaches for something under the bed before abruptly resuming sex. The camera pans below the bed to display Tramell's weapon of choice—an ice pick—implying that she could kill Curran and wants to do it.

Fourteen years after the events of the first movie, Tramell speeds through London in a sports car with Kevin Franks, an English football player. After taking Franks' hand to masturbate herself and reach orgasm, Tramell crashes the car into the River Thames and ultimately leaves Franks to drown. When Scotland Yard finds evidence of her culpability in the death, Tramell is made to attend therapy sessions with a court-appointed psychologist, Dr. Michael Glass (David Morrissey). At her trial, Glass testifies that Tramell is a narcissist who suffers from a pathological "risk addiction", showing no regard for right or wrong. However, Glass' testimony is deemed insufficient, and Tramell goes free.

Tramell begins playing mind games with Glass, who finds himself becoming both frustrated and increasingly intrigued by her. Eventually, he succumbs to temptation and begins an illicit affair with Tramell. However, following the murder of his ex-wife's partner—a journalist planning to write a negative story about Glass—he suspects that she is trying to frame him for the killing. As more people close to Glass turn up dead, his obsession with Tramell grows to the point where it threatens his career and livelihood. In the meantime, Glass conducts a survey for the detective Spt. Roy Washburn (David Thewlis), who has taken the Trammell's case and he is now investigating the murders, and discovers aggravating elements for his earlier professional life. Eventually, Glass himself can no longer tell right from wrong and now he suspects that everything was designed by the corrupt officer in order the latter to nail the writer.

During Glass' confrontation with Tramell, she reveals that her latest novel is based on the present situation, featuring characters based on herself, Glass, and the victims. Tramell gives to Glass a draft of her new book, in which suggests that her next victim is his colleague, Dr. Gardosh (Charlotte Rampling). However, this turns out to be a ruse tricking Glass into having a violent confrontation with Gardosh and subsequently shooting Detective Washburn. Glass is subsequently committed to a mental hospital where Tramell reveals him the whole plot of her latest book called The Analyst, which had a better ending thanks to him, and flashbacks are shown of Glass committing all the murders. The novelist tells him to come back soon, because she misses him, and leaves with a wicked smirk on her face. Glass still sitting in his wheelchair takes the book on his hands and an enigmatic spasmodic movement is erased on his lips.

Catherine Tramell, again played by Sharon Stone, has a cameo in the 1993 film Last Action Hero starring Arnold Schwarzenegger.