On this episode of "Notes on a Scene," Paul Graff, the VFX Supervisor, and Christina Graff, the VFX Producer of "Stranger Things," explain the special effects used in season 2. Paul and Christina discuss how they made the Duffer Brothers' ideas into reality, the five stages of the demodog Dart, the snowy particles in the Upside Down, and the Shadow Monster that Eleven fights at the climax of the season.