Star Trek - The Original Series, Episode 37: The Changeling [VHS]
After destroying 4 billion people in the Malurian star system, a 21st- century NASA probe calledNomad--carrying friendly greetings to whatever  unknown, extraterrestrial race might find it--has a violent encounter with theEnterprise, nearly blowing the starship out of space. Hoping to sidestep  another attack, Captain Kirk (William Shatner) and Mr. Spock (Leonard Nimoy)  invite the diminutive, computer-driven, impossibly powerful spacecraft aboard to  learn how its peaceful mission was supplanted by a program to destroy life.  Written by John Meredyth Lucas, who was intrigued by the idea of a sentient,  almost godlike machine that turns against its creator, "The Changeling"  transcends, fortunately,Star Trek's cash-strapped special effects  department to become a compelling drama. (Let's just say thatNomadlooks  like a cross between the Tin Woodman and a 1960s beach radio.) Particularly  memorable is Spock's mind-melding scene withNomad, in which the Vulcan  is shaken by the probe's chaotic memories of being captured by a machine planet  and given destructive impulses. FrequentTrekdirector Marc Daniels was  particularly proud of the way his crew madeNomadappear capable of  independent movement: There was one model for hanging from a wire, a second for  standing on a floor, and a third for riding on a dolly (to get a sinister,  point-of-view traveling shot). If "The Changeling" sounds vaguely familiar, it  should: The script was rewritten as the basis forStar Trek: The Motion  Picture.--Tom Keogh