Star Trek has a long history of doubles and imposters, and while these generally tend to last for only one episode, some have been able to fool friends, colleagues, and viewers for longer periods of time. Since Halloween is a time when people like to wear costumes and masks and pretend to be someone else, the start of the spooky season seems a fitting time to share our list of some of Star Trek’s villains who were most successfully disguised as heroes.
The Changeling Who Replaced General Martok
One of a few changelings who was sent by the Founders to replace people they believed could be used to sow chaos in the Alpha Quadrant, the Martok Changeling fooled us for years. While hunting saber bear on Qo’noS, the real General Martok was captured by the Founders and imprisoned at Internment Camp 371. During the next two years, the changeling they installed in his place killed one of Martok’s commanders, launched an attack into Cardassian space, and began a year-and-a-half-long conflict between the Klingon Empire and the Federation.
He even attempted to kill Gowron and to take his place as Chancellor in order to keep that conflict going, until he was discovered and exposed by Odo, leading to his death.
The Changeling Who Replaced Julian Bashir
Another one of the spies sent by the Founders to destabilize relationships in the Alpha Quadrant, the Bashir Changeling was put in place to assist Dominion forces, facilitating their passage into Cardassian space and concocting a plot to cripple Klingon, Romulan, and Federation forces. This Changeling managed to fool people for about a month, including Julian’s best friend Miles O’Brien, with whom he even played racquetball and darts. He also was able to sabotage Deep Space Nine’s emitter away, foiling a plan to close the wormhole and prevent Dominion forces from passing through.
The Changeling was intercepted and killed during his attempt to use a runabout to destroy the Bajoran sun.
The Transporter Double Who Replaced Will Riker
Established in Star Trek: The Next Generation, Thomas Riker is a copy of Will Riker who was created in a transporter accident. In the Deep Space Nine episode “Defiant,” Thomas had joined the Maquis and posed as Will to steal the USS Defiant with Major Kira on board.
He took the Defiant to the Orias system, a location in Cardassian space where he hoped to attack a facility where the Maquis believed the Cardassian were building a fleet of warships. He was instead intercepted by the Cardassian and Sisko negotiated with Dukat for Thomas’s surrender.
The Mirror Universe Variant Of Garbiel Lorca
Throughout the first season of Star Trek: Discovery, the captain of the Discovery, Gabriel Lorca, is a dubious figure, and it is unclear whether he is to be trusted or not. By turns, he can seem like a principled Starfleet captain who has a drastically different way of accomplishing things or someone with ill intent who does not belong in the captain’s chair.
The latter turns out to ultimately be true as it is revealed that the person we have seen throughout the season as Gabriel Lorca is actually the Mirror Universe variant of the Prime Universe Lorca.
While it is assumed that the Prime Universe Lorca was killed, his true fate is never definitively confirmed. Mirror Lorca was killed in the Mirror Universe.
The Cardassian Who Infiltrated Starfleet
Seska was a Cardassian agent who was disguised to look like a Bajoran and infiltrated the Maquis ship Val Jean, under the command of Chakotay. However, when the crew of the Val Jean was merged with that of the Voyager, she was forced to serve among the Voyager crew. Eventually, her true nature was revealed and she left the ship to join with a Kazon named Culluh, with whom she unsuccessfully attempted to take over Voyager.
During the ensuing conflict, Seska was wounded by an overloaded panel that exploded near her. She did not survive very long after these injuries, though Culluh managed to escape with her baby, whom she had claimed was Chakotay’s.