The mythology arc spins up in a big way with Two Fathers. Written by series creator Chris Carter and Frank Spotnitz, the episode first debuted on 7 February, 1999, and sees the return of Cassandra Spender (Veronica Cartwright), the reveal to Mulder (David Duchovny), Scully (Gillian Anderson) and Skinner (Mitch Pileggi) that CSM (William B….