A vast machine entity in Star Trek: The Motion Picture that grew from a lost NASA probe and came to Earth seeking its creator.
V'Ger was an enormous machine entity hidden inside a huge energy cloud. It destroyed three Klingon cruisers and the Federation's Epsilon IX station on its way to Earth, and the refitted Enterprise under Admiral Kirk was sent to intercept it.
Inside the cloud, the crew found that V'Ger had abducted the navigator Ilia and replaced her with a machine copy to study the crew. They discovered that its core was the old NASA probe Voyager 6, launched from Earth centuries earlier and found by a planet of living machines. They had built it a body so it could carry out its programming to learn all it could and return the knowledge to its creator.
Having learned everything it could, V'Ger wanted to join with its creator. Commander Willard Decker chose to merge with V'Ger and the Ilia probe, and the union created a new form of life that vanished into another dimension.