After the first two episodes concerning alien abductions comes this creepy monster-of-the-week story that concerns a liver-eating mutant named Eugene Tooms. I know this is highly regarded by many as classic X-Files, but I found this quite slow in places, and not as exciting as Deep Throat. Nevertheless, there are some creepy bits here, such as the opening shot of Tooms under the pavement, and there's also some great humour from Mulder and Scully.
Scully: Is this what it takes to climb the ladder, Colton?
Colton: All the way to the top.
Scully: Then I can't wait till you fall off and land on your ass.