Krono' is a gigantic, slow-moving extraterrestrial robot that came from outer space and the titular main antagonist of the 1957 black-and-white sci-fi movie "Kronos" (also known as "Kronos, Destroyer of the Universe").
What appears to be a large saucer shaped meteorite crashes into the Pacific Ocean near Mexico, following an unexplained break-in and assault by a deranged man at a secret U.S. research facility. The crashed meteorite soon reveals itself as an even greater menace than first believed, with grave implications for the survival of the human race.
A gigantic machine, Kronos attacks power plants in Mexico, draining them of their energy. In doing so, Kronos grows in size, becoming larger as it consumes more and more energy. Kronos is discovered to be an accumulator sent by an alien race that has exhausted its own natural resources. They have sent Kronos to drain the Earth's power and return it to their own dying planet. A scientist, under control of an unseen alien presence, suggests fighting Kronos by dropping an atomic bomb onto it using a B-47 Bomber, which is done. Kronos only absorbs the bomb's power and grows to titanic size. It threatens to drain the world's cities and starve the Earth of power, but scientists devise a plan to reverse Kronos' polarity, which causes it to feed on itself. Kronos explodes and the Earth is saved.