5 Times Star Trek's Transporters Malfunctioned, With Bizarre Results

Throughout the history of "Star Trek," there have been several versions of the U.S.S. Enterprise. But no matter which variant the Starfleet crew was aboard, they always had an integral device — the transporter. Useful for fast teleportation, hauling cargo, or just a quick escape, the transporter was vital to Starfleet's operation. The device digitized materials from their location and reassembled them at the destination they were beamed to.

Disassembling organic human matter, moving them through space, and piecing them back together? What could possibly go wrong? A lot, as it turns out. When going where no man has gone before, accidents are bound to happen. Between alien plants, transformative particles, and rogue energy, technology won't stay unaffected for long. Throughout all the "Star Trek" series, there were numerous times in which beaming the crew up didn't go as planned. Here are five of the most bizarre transporter malfunctions with the craziest results. 

The franchise's inaugural transporter malfunction takes place in Season 1's "The Enemy Within," one of the most memorable "Star Trek" episodes. It was written by horror author Richard Matheson, who was inspired by the characters Dr. Jekyll and Mr. Hyde. While beaming Fisher (Edward Madden) from planet Alfa 177, some yellow ore particles on his clothes interfere with the transporter's particles. As such, when Captain James Kirk (William Shatner) uses it, the device splits Kirk into two versions of himself. 

His "evil side" is an impulsive, aggressive (and alcoholic) narcissist. At one point, he even attempts to assault Janice Rand (Grace Lee Whitney). On the contrary, "good" Kirk is a meek, indecisive coward.
 According to her memoir, Whitney claimed that Shatner slapped her prior to filming a scene in which Janice confronts evil Kirk over the assault. She is crying during the scene, and the slap was intended to put her in an emotional state. In addition to the series' first transport mishap, "The Enemy Within" also filmed the first instance of Spock's Vulcan Nerve Pinch. 

It's one thing to have your conscience and person split in two, it's quite another to become an alternative version of yourself. The crew experiences this surrealism in Season 2's "Mirror, Mirror." When Captain Kirk, Dr. McCoy (DeForest Kelley), Lieutenant Uhura (Nichelle Nichols), and Scotty are beamed back onto the U.S.S. Enterprise, a severe ion storm interferes with the transport. The four crew members are swapped with their savage counterparts from a mirrored universe (on a ship called the I.S.S. Enterprise).

Stuck in the parallel universe, they must pretend to be their mirrored counterparts to the other parallel crew members, including a goatee-sporting Spock (Leonard Nimoy). Even the transporter itself has a distinctive difference in the mirrored universe. Rather than the gold-colored digitizing effect that engulfs the bodies, the tone is instead a multi-colored one. Jerome Bixby, the writer of "Mirror, Mirror," based the episode on a short story he previously wrote called "One Way Street." It was published in "Amazing Stories" 14 years before he wrote his script for "Star Trek."

Out of all the things "Voyager" gave fans, Season 2's "Tuvix" may take the cake. Lieutenant Commander Tuvok (Tim Russ) and Neelix (Ethan Phillips) are beamed up from a planet after harvesting a unique alien orchid, which causes an interference. As a result, both crew members' molecules merge, and they form a figure with a single conscience. He goes by "Tuvix," combining the names of both original beings.

Captain Janeway (Kate Mulgrew) performs a radioactive procedure that unfuses Tuvix and restores Tuvok and Neelix. The Doctor (Robert Picardo) is unable to perform the procedure, as it would violate his code to bring harm to Tuvix, who begs to not be killed. Aside from the episode featuring such a bizarre transporter accident, it's noteworthy for its ethical dilemma concerning Tuvix's right to exist. Janeway's decision has been the subject of divisive arguments among trekkies. During a 2024 panel, Tim Russ defended the captain's decision, stating "He's an anomaly, whereas the crew people that he has replaced already have a family, we have lives."

As crazy as the series' transport mishaps could be, they were not always grotesque or (overtly) dangerous. Sometimes the results were more lighthearted, as was the case in Season 6's "Rascals." Captain Picard (Patrick Stewart), Ensign Ro Laren (Michelle Forbes), Guinan (Whoopi Goldberg), and Keiko O'Brien (Rosalind Chao) traverse through an energy anomaly while riding in a shuttlecraft. When they get transported, the anomaly physically reverts their bodies to pre-pubescence, but their intelligence and memories remain intact. 

The transporter mishap made for some of the best comedy on "Next Generation." The dynamic between Keiko and her husband Miles (Colm Meaney) after she's de-aged is hilariously awkward. Writer Ronald Moore initially found the idea too absurd when he was handed the episode's script. It had gone through a large amount of rewrites before he received it. During an interview for Captains' Logs: The Unauthorized Complete Trek Voyages, he expressed disdain for the episode. "It was not my favorite assignment and it was a difficult show to write," Moore lamented.

One of the most bizarre transporter malfunctions happened before the series began, but its consequences were only revealed in Season 6's "Second Chances." When the crew visits Nervala IV to gather things left during an evacuation eight years ago, they discover a duplicate version of Commander William Riker (Jonathan Frakes). During the evacuation, an energy surge from the transporter duplicated Riker while he was teleporting. His other self was left stranded for eight years.

Thomas actually lives through the episode and even makes an appearance in "Deep Space Nine." The transporter chief in this episode, Palmer, is played by astronaut Mae Jemison, the first African American woman to go into space. It was also the first episode directed by Geordi La Forge actor LeVar Burton. When responding to fan inquiries on the official "Star Trek" site about playing dual roles, Frakes said he thought it was intriguing. "I found that the psychological implications fascinated me and I wasn't a good enough actor to find much nuance between the two."