While watching “The Day the Earth Stood Still” (1951 version) (***1/2) my son and I immediately recognized the failsafe words “Klaatu barada nikto” from “Army of Darkness” (****). If you believe the so-called experts (and we do) “Klaatu barada nikto” is the most famous phrase in science fiction. It has been referenced repeatedly in popular culture. We will ignore the substantial Wikipedia article entry on the subject and plant our own flag here, now.