Foul Appearance
Regenerate
Block
Guard
Nurse Mildred Ratched is the head administrative nurse at the fictional Portland State Mental Hospital, where she exercises near-absolute power over the patients' access to medications, privileges, and basic necessities such as food and toiletries. She capriciously revokes these privileges whenever a patient displeases her. Her superiors turn a blind eye because she maintains order, keeping the patients from acting out (either through antipsychotic and anticonvulsant drugs or her own brand of "therapy", which consists mostly of humiliating patients into doing her bidding). Her greatest success is with the stuttering, suicidal Billy Bibbit, who is so terrified of her that he does whatever she says.
When Randle McMurphy arrives at the hospital, however, her dictatorial rule is nearly toppled; he not only flouts her precious rules with impunity, but encourages the other patients to follow his example. Her attempts to cow him into submission — at first with threats and mild punishments, then with shock therapy — are unsuccessful. If anything, they only make him more defiant.
The last straw is when McMurphy sneaks two prostitutes into the asylum to relieve Billy of his virginity. Ratched threatens to tell Billy's mother about the transgression. Since Billy fears his mother as much or more than he fears Ratched, the threat frightens him into committing suicide. Enraged, McMurphy attacks and nearly chokes Ratched to death.
In retribution, Ratched has McMurphy lobotomized. Another patient, Chief Bromden, later smothers McMurphy as a kind of mercy killing. However, while Ratched's main antagonist has been removed, her control over the other patients is gone. She can no longer speak, at least not very well — McMurphy damaged her vocal cords when he choked her — and the other patients can now think for themselves; Ratched can no longer intimidate them.