Joker (2019 movie)
Arthur sneaks into a private event and confronts Thomas, who tells him that Penny is delusional and not his biological mother. In denial, Arthur visits Arkham State Hospital and steals Penny's case file; the file says Penny adopted Arthur as a baby and allowed her abusive boyfriend to harm them both. However, Penny claims that Thomas used his influence to fabricate the adoption to hide their affair. Distraught, Arthur returns home and enters Sophie's apartment unannounced. Frightened, Sophie tells him to leave; their relationship was merely a figment of Arthur's imagination. The following day, Arthur kills Penny at the hospital.