Ex-UFC Fighter -- Psychedelic Plant ... Told Me to Change Careers

Former UFC fighter Kyle Kingsbury needed post-MMA career guidance -- so he turned to an ancient hallucinogenic concoction to show him the way ... and it worked.

Kingsbury -- who famously flashed a pair of "Legalize Gay" undies before his July fight for "UFC On Fox" -- initially said he wanted to become a firefighter following his final bout.

But after the fight, Kyle still had some doubts -- so he turned to a shaman who brewed him up a cup of Ayahuasca ... a hallucinogenic herbal drink that people use to go on a vision quest.

And after a trippy ceremony ... with some vomiting ... Kyle came to a revelation -- he should open a gym in Costa Rica to share his fighting talents with others.

"I’m going to be doing what I love," Kingsbury says ... "lifting, fighting, being at a gym."

Kingsbury says he'll be taking his fiance and business partner along for the ride, and expects to have everything up and running by winter 2015.

His only fear -- "I’ve recently learned they have HUGE crocodiles so that’s a little scary."

Good luck!