It Conquered the World is a 1956 science fiction film about an alien from Venus trying to take over the world with the help of a disillusioned human scientist. It was directed by Roger Corman, written by Lou Rusoff (with uncredited contributions by Charles B. Griffith), and starred Peter Graves, Lee van Cleef, Beverly Garland, and Sally Fraser.

Plot synopsis

Dr. Tom Anderson (Van Cleef), an embittered scientist, has picked up the voice of a Venusian alien in his radio transmitter. The alien wants to take over the world with its mind-control devices and thus make a new home for itself, but claims only to be bringing peace to the Earth through the elimination of emotions. Anderson agrees to help the creature in this ploy, even recommending that the creature assimilate his friend Dr. Nelson (Graves) and his wife (Fraser). The alien's first action is to suppress all electric power on Earth, including the ignition systems of motor vehicles, leaving Dr. Nelson resorting to riding around on a bicycle.

After killing a flying bat-like creature which carries the mind-control device, Nelson returns home to see his wife is assimilated and, as she attempts to assimilate him with another bat creature, he kills her. By this point, the only people left that are not mind controlled are Nelson, Anderson, Anderson's wife, and a small group of soldiers camping in the woods. Dr. Nelson finally persuades the paranoid Anderson that he has been wrong about the alien's motives and that he has made a horrible mistake, allying himself with a creature bent on world domination. They hurriedly leave when they discover Tom's wife has picked up a rifle and gone to the alien's cave to try to kill it. The monster succeeds in taking the life of Mrs. Anderson before the two doctors make it to her rescue. Finally seeing his hubris and the loss of everything he holds dear, Dr. Anderson kills the monster, sustaining lethal wounds of his own in the confrontation.