The last surviving creature of planet M-113, a humanoid with large suction cups on its
hands. This individual had caused the death of Nancy Crater before transporting up to the Enterprise, where it was killed when it threatened the life of Captain Kirk. The M-113 creatures possessed an extraordinary hypnotic ability to appear with the identity of someone known to their prey, and used this ability when hunting in order to obtain the salt they need to survive. (The M-113 creature is popularly known by many Star Trek fans as the Salt Vampire, although this name did not come from the episode itself.)
The M-113 Creature Can Be Seen In The Episode, "The Man Trap."