32-year-old Eblen was shopping at a local Home Depot in Florida recently when a social media prankster named ImReddttv approached Johnny and his lady friend wearing the Apple Vision Pro, and things almost instantly got off to a bad start.

"I'll tell you right now, I'm pretty sure I can bag her," Redd said, standing in front of the couple.

Credit to Johnny's spidey senses ... he seemed to instantly feel something was off, and even pointed out a guy in the cut who was surreptitiously holding a camera.

Redd brushed off the dude filming, and carried on with the prank, saying ... "What's up little man?" to the MMA champion.

He continued ... "Sweetheart, you need to be with a real big man like me," before asking Eblen if the woman was "his girl."

That's about when Johnny's patience wore out (he lasted a lot longer than most would've), saying, "If you say something disrespectful I'll f*** you up!"

Eblen and the woman started walking away, and Redd followed. Johnny then stopped and began walking toward the prankster ... and you get the feeling it was about to turn bad for the social media star.

That's when Redd revealed he'd been sent by Brian Butler-Au, Johnny's manager, to troll the fighter. Tension was instantly broken, and Johnny had a good laugh.

Not too long after the prank, Johnny hopped aboard a jet and flew across the world to Saudi Arabia ... where the Bellator middleweight champ is fighting PFL light heavyweight champ Impa Kasanganay on February 24 in Riyadh.