This is efficient as b-horror, but ultimately a silly 'monster' episode. We get atomic mutation from the other side of the Wall but somehow the thing ends up in New Jersey sewers, body horror, some murky sewer atmosphere, but it just bogarts belief that they could, and did, get away with an episode such as this. It does feed the conspiracy angle, but so what?
The whole X-File point is that we don't just suspect, we know that something is out there that we can't fathom, of course the series executed several half-baked attempts to muddle the waters with whether or not it is all a big hoax, but the fact remains; we know there's stuff out there that shouldn't be.
So the question raised here, is what does it say about the show that this can be bogged down to a slimy, worm-like monster? It's a creative disaster as far as I'm concerned.