Giant creatures that resemble slugs, the orange Lactrans each have individual reddish markings on their backs and faces. They have two yellow eyes and a trunk which ends with three grasping tentacles. The Lactrans are immensely intelligent, eons past any known race in the Federation. Communicating in a telepathy that is too fast and complicated for Mr. Spock to get anything but fleeting images from, the Lactrans capture the crew of the S.S. Ariel, and a few weeks later Captain Kirk, Spock and McCoy, in 2269 to keep them as specimens in their intergalactic zoo. The Lactran females find the humans ugly, while the children are frightened of the simple creatures.