Killers from Space

The 1954 movie Killers from Space stars Peter Graves as Dr. Douglas Martin, a nuclear scientist who is abducted and then possessed by aliens. The aliens want to steal power from earth for some reason or other, and there are giant insects. Dr. Martin supposedly died in a plane crash, but then he gradually starts to remember who he is, just in time to save the day. Killers from Space has all the elements you'd expect: aliens, atomic bombs, and mutant monsters, but that doesn't mean it was particularly good. (Thanks, WTM!)