Oddities and curiosities today kids!
1965 (or close to it) saw the creation and possible test release by Topps of two old movie staples: King Kong and Flash Gordon. These black-and-white sets were either tested or just printed up for internal use and are fairly legendary rarities today. A seller on eBay purports to have proof boxes for both but I think, at best, they are mockups and I'm not 100% convinced they were created by Topps at the time the sets were being considered for release, although the odds greatly favor it I think.
Here's King Kong, with folded-over indicia:
Meanwhile, well across the sci-fi universe: