Fang

Gina collapses and is hospitalized. Dr. Decanthian reveals that she has Stage 5 Parkinson's disease and will require 24/7 care. Billy dissociates on hearing the news, flashing back to a dead rat he found in a field.

Billy becomes attracted to Gina's new caregiver, Myra Valenti. Myra shows interest in Billy's drawings, sparking an awkward but promising connection.

A rat is found in Billy's bathtub and bites him, leading to hospitalization and a tetanus shot. He soon notices strange bumps and wounds forming on his skin.

Mr. Wolfson lectures Billy at the meat processing warehouse about not skipping work, not realizing Billy had been in the hospital. The confrontation underscores Billy's fractured tie to his job.

Gina urinates on the floor during a confrontation. Billy tears off a piece of his skin and finds rat fur beneath, which he sketches for Myra; she cautions him and suggests a self-help approach.

Gina forces a height-measuring contest between herself and Myra at dinner, and Gina is revealed to be three inches taller. Billy has a panic attack and notices more rat fur growing on his back.

At a bar, Billy tries to socialize with Danny and Jeff but is interrupted by a vision of a humanoid rat-headed Rat King. The terrifying vision unsettles him and blurs his sense of reality.

Gina confronts Billy in his bedroom in a hallucinatory state, claiming he is Sam, her dead husband, and sexually assaults him. The scene reveals the deepening blurring of reality and delusion in Gina's mind.

Billy dreams of a humanoid rat creature, Dr. Rat, who chants 'We need red meat.' The nightmare reinforces the fracture between Billy's perceptions and the real world.

At work Billy overhears Mr. Wolfson talk about a health and safety inspection and hiding bank documents. He also over hears that Wolfson has $500,000 in cash at his house. Billy buys a lockpick and hunting knife and tells Myra he plans to break in.

During the health and safety inspection, Billy breaks into Wolfson's house and finds large sums of cash. Wolfson is pulled away by a phone call, and Billy hallucinates the Rat King appearing on the living-room TV as he suffers a mental breakdown, ending with him stabbing Wolfson to death.

Billy returns home to find Gina immobile, then stabs her repeatedly, removes her intestines, and cannibalizes part of her. He briefly transforms into a humanoid rat creature as the act completes.

Myra returns home and discovers Billy has killed Gina, then calls the police to report the crime. She becomes a witness to Billy's downfall and the ensuing investigation.

Billy is sentenced to stay in a mental hospital and is diagnosed with autism, schizophrenia, and severe psychosis. He expresses a desire to get better, and a drawing of a humanoid rat creature hangs in his padded cell.