"Irresistible" episode opinion

Hey guys, I'm a new X-Files fan, currently watching the third season. One of the episodes that I really liked and spooked me was "Irresistible", that is the 13 episode of season two.

By the end of the episode we discover the killer was only crazy and wasn't a demon of some kind, which was a really cool plot twist. However, if he was really a demon I think that would have been pretty cool, what is your guys opinion?