Kronos

Scientists at a "Top Secret" atomic research laboratory are taken over by strange fantastic control devices launched from an orbiting space ship inhabited by a hostile super-intelligence from beyond the stars. Simultaneously, a gigantic flying saucer crashes in the Gulf of Mexico and Kronos, a giant metallic monolith monster, emerges. Unstoppable, it slashes across the countryside, draining the earth of all it's electrical energy and beaming it into space. Kronos, a weapon so perfect in design it absorbs a direct hit by a Hydrogen bomb and becomes that much more powerful! (official distributor synopsis)