thraxman: I loved the X Files since I first saw it about 15 years ago being repeated, but I can’t help but think they used their best monster first. They never seemed to do any better then the mutant Tooms for the monster of the week. He was really creepy, interesting, in some ways believable (he could bend and stretch but not to the extent of the fantastic four guy) and they deliberately left a huge amount of unanswered questions about him and what little they did reveal were all guesses and assumptions. Why did he have to rip people to pieces and eat their organs? What original caused his mutations? Why did he have to keep hibernating every thirty years and then awake and randomly kill five people? If he was over 100 years old (he looks like he’s in his late twenties) how did he live that long and did he have any kids out there like him? The only guess they made was his mutations did it all but the show didn’t even attempt to explain what was really wrong with him. You had no clue what he was and where he came from and it worked brilliantly.
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Breja: Tooms was great, but there were quite a few other monsters of the week that I liked even more. There's the superb Folie a Deux episode, with it's bug-monster turning corporate drones into actual zombies, but no one can see it except for one guy, and that episode superbly well illustrated the friendship between Mulder and Scully, while also having a very creepy and unexplained monster. There was "the pusher", the guy who could make anyone do anything just by talking to them, even talk them into having a heart attack over the phone. But my favourite monster of the week might actually be from season 8 - Via Negativa. The premise might sound a bit trite- a guy killing people in their dreams, but the way it's done is superbly creepy, and the final sequence is one of the best, most tense damn things X-Files ever did. And the another great thing about it is how it pretty much couldn't have worked as well with anyone but Doggett, someone for whom all this paranormal stuff is new, and it isn't fun or fascinating in a scientific way, it's just messed up and he's genuinely scared in a way we've never really seen Mulder or Scully.
Who was the other guy who appeared twice, the necrophiliac and cannibal serial killer? They hinted he was Satan himself in disguise several times.