American Psycho
Christian Bale plays one of the most meticulous and unhinged serial killers of all time in American Psycho. After the murderous Patrick Bateman confesses to his lawyer, Harold (Stephen Bogaert), the story begins to unravel. The body parts that Bateman had once been storing in Paul Allen's (Jared Leto) apartment have vanished, and a realtor says that nobody by that name ever lived there. Later, Harold explains that he just saw Paul Allen in London, meaning that Bateman couldn't have actually killed him.
Hereditary
Ari Aster's debut horror film, Hereditary, made waves upon its release for its shocking twist in the first act. After the death of their grandmother, Peter (Alex Wolff) is forced to bring his younger sister, Charlie (Milly Shapiro) with him to a house party, where she has an allergic reaction to nuts. While racing to the hospital, Charlie is decapitated by a telephone pole. In a second twist, Peter and Charlie's mother, Annie (Toni Collette) contacts what she believes to be Charlie's spirit, but in reality, she has summoned King Paimon, a demon who serves Lucifer. Their grandmother was in a cult all along, and Peter's entire family dies in various, gruesome ways. Peter is then made into a vessel for King Paimon by members of the cult.