In the great sprawling universe of Star Trek, Gene Roddenberry introduced us to the notion of alternate realities and parallel universes early on in the second season of The Original Series. A simple transporter accident and we saw what could be and what shouldn't be, all summed up in the most perfect goatee in cinematic history.
This would not be the last time that, as an audience, we were treated to a what if? One of the most fun things to do in science fiction is to take what is familiar and flip it upside down, playing with expectation and, in honesty, giving the actors something new to do!
Thankfully this is a trope that is not confined to the mirror universe and beyond. There are many examples throughout the franchise of 'what if' episodes, shows where the characters are pulled out of what is established and then dropped into a situation that challenges them. It is one of the best ways to keep a science fiction show from going stale.
While not every time that this happens is a success, and even some of the stronger arcs would face an amount of fatigue by the time they came to a close, the episodes on this list represent a strong selection of what makes alternate reality episodes enjoyable on Star Trek.
Writer. Reader. Podcast Host. I'm Seán, I live in Ireland and I'm the poster child for dangerous obsessions with Star Trek. Check out my weekly podcast on all things....well all things film! https://anchor.fm/sean-ferrick