When producers realized Duncan Young would be playing Emperor Staleek later on, they digitized his voice for this episode, so that he could use his regular voice as Staleek.
"Klaatu barada nikto" is a phrase that originated in the 1951 science fiction film The Day the Earth Stood Still. The humanoid alien protagonist of the film, Klaatu (Michael Rennie), instructs Helen Benson (Patricia Neal) that if any harm befalls him, she must say the phrase to the robot Gort (Lockard Martin).