Supernatural celebrates its 200th episode  tonight at 9/8c on The CW. Check out a preview of “Fan Fiction” below — When Sam (Jared Padalecki) and Dean (Jensen Ackles) investigate the disappearance of a teacher, they are stunned to see the school is putting on a musical based on their lives.  Familiar faces abound in this milestone episode.  Phil Sgriccia directed this episode written by Robbie Thompson.