Episodes 20 & 21 of The X-Files season 1 are both excellent!
Darkness Falls is a wholesale tribute to Ice (or possibly Chris Carter deciding he could also do a bottle episode with paranoia and in-fighting) just set out in the wilderness with bugs for enemies and an apparent inadvertent environmental theme.
Tooms is the unexpected sequel to near universal favourite episode Squeeze. Eugene Victor Tooms is back, but damn, is his doctor in love with him or not? Highly unprofessional. We debate whether the episode should really be centred more on Scully than Mulder. Also returning is Cigarette Smoking Man who has taken up residence in new on-going character Walter Skinner's office.