Complex sentence: The scene where Butters watches a video he recorded of his night sleeping is a reference to the film "Paranormal Activity", and the final scene with Lu Kim is a reference to Norman Bates in the penultimate scene from "Psycho".
Split into simpler sentences: The scene where Butters watches a video he recorded of his night sleeping is a reference to the film "Paranormal Activity". The final scene with Lu Kim is a reference to Norman Bates in the penultimate scene from "Psycho".