Star Trek Just Doubled Down on Its Wildest Body-Switching Concept

Body switching is a classic sci-fi trope. From Freaky Friday to Farscape, and of course, most of Quantum Leap, the idea of the consciousness from one person inhabiting the body of a different person will never stop being the fuel for speculative stories that are both hilarious and profound. But, when Star Trek invented the “joined” species of the Trill in 1991, it took the body-switching/body-surfing trope to a new level. While a specific Trill symbiont might live for several hundreds of years, this slug-like creature generally inhabited a humanoid host. This “joining” often created a new hybrid personality each time, sort of like Time Lord regeneration from Doctor Who mashed up with internal alien parasites from Alien; a chest-burster that never burst, but just stayed in you forever.

And if all of that wasn’t wild enough, on June 12, in the episode “Facets,” 1995, Star Trek: Deep Space Nine added a new wrinkle to Trill canon. Not only were the memories of all the previous hosts alive and well in the current symbiont, but, through a process called “zhian’tara,” a specific host’s personality could leave the symbiont and enter into the body of... anyone! Basically, this was Trill joining via spacey magic, and now, 29 years after “Facets,” Star Trek: Discovery is doubling down (tripling down?) on this very specific form of consciousness transfer in the Season 5 episode “Jinaal.” Spoilers ahead.

The Trill host trick

Although the Trill were established in The Next Generation episode “The Host,” the vast majority of Trill canon comes from Deep Space Nine, thanks to the presence of Jadzia Dax, who later, in Season 7, switched hosts and became Ezri Dax. But, in the memorable Season 3 episode “Facets,” Jadzia’s previous host, Curzon, left her body through the zhian’tara process and settled in the body of the station’s resident shapeshifter, Odo. From that point, Odo’s entire personality was merged with Curzon’s, which put everyone on the station in a deeply uncomfortable position.

As a stand-alone episode of DS9, “Facets” remains a fantastic story about memory, regret, and what one generation owes the next. But, the legacy of “Facets” is easily the concept of zhian’tara, which was used to save Gray Tal’s consciousness in Discovery Season 4, and now, in Season 5, is being employed again to unravel an 800-year-old mystery.

Discovery’s return to Trill

The planet Trill was first seen in DS9 in the episode “Equilibrium,” but Discovery has actually visited the planet more times, starting in the Season 3 episode “Forget Me Not,” and now again, in “Jinaal.” This time the need to transfer the memories of one previous Trill host into someone else is all connected to the secrets Jinaal Bix has about researcher of the Progenitors in the 24th century.

After transferring Jinaal’s consciousness into Culber, the entire personality of our stalwart Starfleet doctor changes, and, just like “Facets,” he suddenly becomes cockier, and more evasive. If you watch “Facets” right after watching “Jinaal,” the parallels are clear. While Curzon’s secret was connected to something personal, Jinaal’s secret has broader implications. Turns out, Federation scientists were working on cracking the Progenitor tech during the era of the Dominion War, and so they decided to bury any knowledge of the technology to prevent any planet or government from weaponizing their research.

Interestingly, this detail dovetails with Picard Season 3 a bit, in which we learned that Section 31 was pushing different Federation scientists to weaponize the organic nature of Changelings. Basically, the Dominion War created a lot of corrupt scientific research within the Federation, making the top-secret Daystrom labs that Riker, Raffi, and Worf raided perhaps just a small sample of the horrible top-secret weapons the Federation has developed.

What Discovery does is make it clear that Jinaal did the right thing at the time by hiding the research — even if that doesn’t help our heroes at the moment.

A classic Original Series nod

Of course, within the canon of Trek, the Trill weren’t the first time the franchise explored the concept of sharing consciousness. Spock transferred his katra to Bones in The Wrath of Khan, and Kirk switched bodies with Janice Lester in the controversial final TOS episode “Turnabout Intruder.”

But, one wonderful 1968 episode from TOS Season 2 — “Return to Tomorrow” — featured ancient beings borrowing the bodies of Kirk, Spock, and Dr. Ann Mulhall in order to build more permanent, android bodies. When the ancient being of Sargon enters Kirk’s body, one of the first things he says is: “Your captain has an excellent body.”

Now, 56 years later, when Jinaal finds himself in Culber’s body, he says something similar: “Wow, this guy really works out!”

Across decades of internal canon, Star Trek can make the same body-switching joke, and make it work, in any century.

Star Trek: Discovery Season 5 drops new episodes on Fridays on Paramount+.