This was the final film made under Merv Griffin's contract with Warner Brothers. His salary never rose above the relatively paltry sum of $250 a week, and after "Phantom" tanked, Griffin abandoned his hopes of ever being a leading man in the movies, concentrating instead on succeeding in television.
When told that he'd been cast in this film as a student studying at the Sorbonne, Merv Griffin supposedly remarked: "Me, playing a Frenchman, with my night-train-to-Dublin puss?!?"
When first released in the UK, this film's violence caused it to be classified as "Adult Entertainment," and when it is shown on Turner Classic Movies now, it is rated "TV-14," the broadcast equivalent of a PG-13 theatrical rating.
Since it was shot with lenses and lighting designed to accommodate the 3-D process, "flat" prints of this film (those used in theatres without 3-D projection equipment and the print from which video masters were created for television showings) had to be struck from a second generation negative. As a result, TV versions of this film have a dark and blurry quality, unlike its appearance in 3-D.
Debut of actress Dolores Dorn.