The phrase "regular, everyday, normal motherfucker" was popularized by the 2008 Jon Lajoie hit "Everyday Normal Guy 2" and revitalized as an audiobyte on multiple social media platforms (such as TikTok and Instagram).
Meant initially to signify an "average joe" cliché, or an individual who is so ordinary it is extraordinary, the phrase has come to be used as a tongue-in-cheek audio track for videos of individuals preforming impressive displays.
Usage seems to be in an ironic phase.
"Yo, I just got footage of a dope trick shot, I'm gonna post it with the 'regular, everyday, normal motherfucker' audio!"