The Dyatlov Pass Phenomenon states that whenever an online content creator runs out of original content, it is only a matter of time before they create and post a video about the Dyatlov Pass incident of 1959. The Dyatlov Pass incident is about the deaths of 9 Russian hikers who died in the Ural Mountains under mysterious circumstances in early February, 1959.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.