He also appeared numerous times in episodic television throughout the 1960s, including the portrayal of the villain on no less than three episodes of Mission: Impossible. He appeared in four episodes of the eight-episode CBC docu-drama The National Dream, as the "railway general" william Cornelius Van Horne. Several years after his Battlestar Galactica tenure, Colicos again ventured into science fiction. He portrayed power-mad Mikkos Cassadine, a demented scientist bent on freezing the world on the ABC soap opera General Hospital during the height of the "Luke and Laura" frenzy. He also was the voice of the X-Men villain Apocalypse/En Sabah Nur (1993–1995) in the Fox Kids animated X-Men television series in the nineties, and twice played rogue alien Quinn in the first season (1988–1989) of War of the Worlds.