(John Arndt). Kirk tells Professor Crater that he and his wife should stay aboard the Enterprise until they find out what killed Darnell. Crater then runs off trying to find Nancy. Nancy kills both Sturgeon and Green; their faces show the same mottling as Darnell. Nancy assumes the form of Green, and meets Kirk and McCoy. They beam back up to the ship with Sturgeon's body. "Green" roams the corridors, stalking several crew members, killing one. It shapeshifts into the form of McCoy after confirming that the real McCoy has taken a sedative to sleep. Meanwhile, Spock confirms that scans show only one person, Crater, on the planet; Kirk and Spock beam down to capture him. They find Green's body before Crater tries to frighten them away with phaser fire. After they stun him with a phaser beam, the dazed Crater reveals that the real Nancy was killed by the creature – the last member of a long-dead civilization of shape-shifters who feed on salt – a year earlier. The creature continued to take on the appearance of Nancy out of affection for Crater, and he has been feeding it, comparing it to the "now-extinct buffalo". Kirk informs Enterprise of the creature's intrusion, as the landing party and Crater transport back to the ship. Crater refuses to help them identify the creature, so Kirk orders the fake "McCoy" to administer truth serum. Kirk arrives in sickbay to find Crater dead and Spock injured; Spock's Vulcan blood made him incompatible with the creature's needs. Back in its "Nancy" form, the creature goes to McCoy's quarters. Kirk arrives with a phaser to provoke the creature into attacking. McCoy gets in the way, giving the creature the opportunity to attack Kirk. The creature reverts to its natural appearance and starts to feed on Kirk. McCoy opens fire with his phaser. The creature changes back into the shape of "Nancy" to plead for its life as McCoy continues firing and kills it. As Enterprise leaves orbit, Kirk comments to Spock that he was thinking about the buffalo. Production Writing "The Man Trap" appeared in Gene Roddenberry's original pitch for Star Trek as the title of a show with a different plot: the crew face several apparitions that are "wish-fulfilment traps which become as real as flesh and blood"; the traps increase in subtlety until the crew struggle to differentiate between apparition and reality. Lee