Character profile and behind the scenes featurette created for the video release of the three-part episode "Biogenesis" / "The Sixth Extinction" / "The Sixth Extinction II: Amor Fati".
As fabulous as Mulder and Scully were (and they were fabulous) having Skinner was integral to the x files family. He loved and protected them and kept cigarette smoking man and others at bay. But he also questioned the agents and himself when it was necessary.
I just re-watched Biogenesis and realized that Scully mentioned Dr. Sandoz’s location to Skinner, and then Skinner was the one who told Krycek where he was, which led to Dr. Sandoz being murdered. Skinner really was a snake sometimes.