A man can walk through walls. Since this is The X-Files, Mulder and Scully are sent to investigate. They find that he can change the composition of objects to pass through them, utilizing electrical charges, which was brought on by a tornado. Right. I think it would have been more plausible had they stolen something out of X-Men and said that his DNA had mutated, or something. Oh well.
The episode is still good, however. It's sufficiently creepy, with a touch of emotion, and a dash of humour (Mulder's one-liners here are especially sharp and witty). The plot is easy to guess but it's still pulled off well. Some of the ideas are cool - the guy writing on the wall with his finger, and the fact that everything he walks through becomes weak and brittle - but the fact that it was brought on by a tornado is just too ludicrous to accept. So check your brain at the door and enjoy. Overall, a decent episode that takes a well-worn idea and wears it out even more.