Tooms has the distinction of being the first sequel to a monster-of-the-week (MOTW) episode. It also has the distinction as being the first appearance of Assistant Director Walter Skinner. Also CSM speaks for the first time in this episode. This is a great episode. It's one of the better sequel episodes. It's not as creepy as Squeeze, but excels in a different way. I love the cinematography used to show Tooms point of view. When he sees a potential victim, he/she is dressed in bright blue and the surroundings turn to black and white. Mulder does his best Columbo impression in this episode. He hounds Tooms and doesn't allow him to kill like he wants. The ending was a bit unbelievable, but other than that, Tooms is another solid season one episode.