A nice article about Al Bender and the "beginning" of the Men In Black phenomena

https://mysteriousuniverse.org/2021/11/the-origins-of-the-men-in-black-thanks-to-albert-bender-part-1/ 

I would respectfully disagree with this being classified as the Beginning.  I think that it's been around much longer, but is interpreted culturally by the experiencer.  And so we get gnomes, demons, etc., but still following the pattern written about above.