J.R.R. Tolkien fans across the globe encountered the seemingly impossible last month: a film version of “The Lord of the Rings” they’d never heard of. There was Gollum gargling in his cave. Except that in this version, he’s speaking Russian, sports orange eye-shadow and has what appears to be bright green cabbage leaves pasted to his head.

“Khraniteli,” or “The Protectors,” was an adaptation of “The Fellowship of the Ring” made in the Soviet Union just months before its collapse in 1991. It aired briefly as a televised children’s program before disappearing for 30 years. The two-part, two-hour-long production is enjoying newfound fame since its producer 5Tv, formerly Leningrad TV, posted it online out of the blue. It has racked up a collective 2.3 million views on YouTube as a new generation revels in its accidental campiness and undeniable sincerity.

No one was more shocked that the film had resurfaced than Georgiy Shtil,...