For decades, Star Trek has been asking questions about humanity, what it means to be alive, and what makes us...us. Sometimes, it even offers an answer to those questions, but more often than not, we're left with bittersweet ambiguity and a lot of food for thought. Other times, seeing the alternative version of a character simply reaffirms why we love the real thing so much. Between transporter accidents, holograms, altered timelines, synthetics, and even more transporter accidents, there are plenty of ways for a Starfleet officer to accidentally 3D print a duplicate they didn't ask for. So while we try to avoid the existential crisis of wondering whether we, too, have a doppelgänger lurking in the shadows, these are some of the most unforgettable alternate versions of beloved Star Trek characters.