5. The Devil In The Dark (Episode 25)
The Plot: The Enterprise tries to stop a monster that is killing miners on the planet Janus IV.
The Screw Up: Kirk and Spock search through tunnels to find the Horta that has been killing the miners. At one point, Kirk says to Spock, "You go left," and he motions to his right, then says, "I'll go right," and motions to his left. Look, I know it's not that big of a screw up, but it is one of the funniest. I just like it, okay? Get off my back. Go back and watch the episode. You'll see it and laugh. Then you'll thank me. You're welcome. I accept your apology.
Cool Trivia: William Shatner's father died during the filming of this episode. He was comforted being with his good friend Leonard Nimoy on the set. In his book
Star Trek Memories, he wrote that this episode, "exciting, thought-provoking and intelligent, it contained all of the ingredients that made up our very best
Star Treks."