10 Scariest Star Trek Episodes Ever
4. The Empath
Star Trek - Season 3, Episode 12
Again, it's not what you see in this episode that makes it terrifying, it's more the descriptions you're afforded and what your imagination can do with them from there. In fact, such was the disturbing power of implication in this episode, it was banned by a number of networks when the show originally aired.
In the episode, while visiting an apparently doomed planet, the crew is repeatedly subjected to torturous experiments by its inhabitants. Dr McCoy, in particular, is subjected to the worst of it, having apparently been both psychologically and physically pulled apart off-screen. Virtually all of his internal organs, according to Spock's assessment, have been abused in some capacity.
In the UK, the episode wasn't screened unedited until 1994, owing to its graphic approach to the subjects of "madness, torture and sadism". While it escaped the same censure in the United States, the episode did carry a warning before it aired to warn viewers about the graphic nature of its content. Again though, it's not the content that's particularly graphic, rather how it plays out in your own mind.