CJ Hancock says he had to be revived after his heart stopped when he collapsed in the ring during a fight.
The Legacy Fighting Alliance star was competing at LFA 26 in Houston on Saturday when the scary moment occurred.
The 32-year-old collapsed in the ring and received urgent medical attention, later taking to social media to reveal how his heart stopped, before he suffered kidney failure.
Hancock says he was brought back to life after being hit by the 'EKG' twice.
"Well I died tonight in the cage," he posted on Facebook.
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"I'm okay. Thanks everyone. I'll reply when I can. My heart stopped, and I had kidney failure , they did cpr and hit me with the defibrillator twice and brought me back.
"Still unsure why it happened. I had a hard weight cut. Doc says I shouldn't fight again.... I'm broken, I guess I'll just be a coach from now on.... I still plan on competing in Brazilian Jiu jitsu and BJJ superfights, when I get better. Thanks to everyone that supported me!"
The issue of cutting weight continued to plague the sport of MMA, with a number of recent incidents highlighting the dangers of the practice.
“It’s a very unfortunate situation where C.J. Hancock took a body kick during his fight,” LFA CEO Ed Soares said in a statement.
“After the kick landed, there was a few second delay, and then he collapsed in the cage.
"Our cutman David Maldonado immediately recognised the problem and signalled to the medical team sitting cageside.
"They were able to resuscitate and stabilise C.J. and took him to the hospital via ambulance where they determined he had suffered kidney failure. C.J. is currently recovering and in the company of his friends and family.”
It was a huge weekend in MMA, with Canadian legend Georges St-Pierre completing a stunning comeback to UFC, beating Michael Bisping by submission to claim the middleweight title after a four-year absence from the octagon.
The 36-year-old choked reigning champion Bisping into unconsciousness at the end of the third round to claim the belt after a thrilling back-and-forth battle on a night when three UFC titles changed hands in New York's Madison Square Garden.
Earlier in the evening, challenger Rose Namajunas pulled off a stunning victory to wrest the women's strawweight crown from Joanna Jedrzejczyk, felling the Pole with a thundering left hand to finish the fight by knockout 3:03 into the first round.
The men's bantamweight title bout threw up another instant classic as TJ Dillashaw floored Cody Garbrandt halfway through the second to win by knockout and reclaim the belt he lost to Dominick Cruz in January 2016.