There was a major Sci-Fi craze during the 1950’s, helped along by the UFO sightings that began after WW2. Another 50’s fad, a brief one, was 3-D movies. The 1953 cartoon “Popeye, The Ace of Space” was released in 3-D. Keep that in mind while watching the video.
This cartoon contains a couple scenes of “alien experimentation” that upset me greatly as a child, despite Popeye escaping unharmed (thanks to spinach, of course). Scanning through some of the later Popeye cartoons released by Paramount, it seems that someone at the Famous studio had a real sadistic streak that crossed the line from cartoon mayhem into something darker and more disturbing.