On October 6, 1967, Star Trek: The Original Series introduced its viewers to a whole new universe in the episode “Mirror, Mirror.” The episode’s premise is that a transporter malfunction causes Captain Kirk and his crewmates to swap places with their doppelgangers from a parallel timeline. In that universe, the United Federation of Planets does not exist. Instead, the Terran Empire reigns, and the crew of that empire’s ISS Enterprise are as ruthless and ambitious as their counterparts on the USS Enterprise are curious and compassionate. As was typical of television of the era, the plot resolves itself by the episode’s end, with each character returned to their original universe. Kirk even manages to convince the mirror universe’s Spock, with his iconic goatee, to bring reform to the Terran Empire, moving it towards the principals of the Federation. “Mirror, Mirror” became one of Star Trek’s best-known episodes. The idea of a parallel “dark” universe has since popped up elsewhere in popular culture and growing a goatee became playful shorthand for turning evil.
