It won an Emmy Award for Outstanding Makeup for a Series.
The Cigarette-Smoking Man's "real" name, CGB Spender, is used for the first time.
This is one of the few episodes in which Mulder says the tagline "The truth is out there."
The official name of the black oil virus, "Purity," is revealed, though it had been assumed since The Erlenmeyer Flask (1994).