Stardate 1531.1: Visiting Professor Crater and his wife (who, before marrying Crater, had a close relationship with McCoy), an Enterprise landing party starts to fall prey to an unknown assailant that seems to drain its victims of salt. Kirk is suspicious – and McCoy alarmed – when the Craters refuse, in spite of the threat, to evacuate their planet. The landing party returns to the Enterprise with an extra passenger – a shape shifter who can assume the shapes of Enterprise crewmembers and who has been living with Professor Crater in the guise of his late wife, whom the creature killed. The creature, in search of salt, sees the Enterprise as a promising hunting ground.
written by George Clayton Johnson
directed by Marc Daniels
music by Alexander Courage
Cast: William Shatner (Captain James T. Kirk), Leonard Nimoy (Mr. Spock), Jeanne Bal (Nancy Crater), Alfred Ryder (Professor Robert Crater), DeForest Kelley (Dr. Leonard McCoy), Grace Lee Whitney (Yeoman Janice Rand), George Takei (Sulu), Nichelle Nichols (Uhura), Bruce Watson (Green), Michael Zaslow (Darnell), Vince Howard (Crewman), Francine Pyne (Nancy III)
LogBook entry by Earl Green