The Devil in the Dark is an episode that perfectly demonstrates the seek out new life aspect of Star Treks message. A mining colony is menaced by something lurking in the tunnels and killing miners one by one. The Enterprise arrives to investigate. In a touching scene that showcases the Vulcan ability to mind-meld with other living beings, Spock merges his mind with that of the subterranean creature, the Horta, as we learn it is called, and discovers it is killing the miners only to protect its offspring. Spock places himself in danger, coming into contact with the Horta, not only to save the remaining miners, but to find the truth behind the mystery and discover an alternative to destroying the Horta. As he says at one point in the episode, to kill a creature that is the last of its kind would be a crime against science.