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.