Conor McGregor's high-strung fight week continued at the UFC 264 ceremonial weigh-ins on Friday night, when he threatened Dustin Poirier's life after a brawl with his opponent.

McGregor will try to avenge his second-round TKO loss to “The Diamond” at UFC 257 in January when the two meet for the third time, with the score tied at one win each.

However, with the odds now favoring his opponent, McGregor appears to have been hell-bent on getting under Poirier's skin throughout fight week.

After his press conference jabs about Poirier's wife appeared to have no effect on the Louisiana lightweight, McGregor got a little dark with his pre-fight prediction while speaking with Joe Rogan after the last faceoff at the ceremonial weigh-ins.

“Joe, this man is going to learn in 16 hours that if you disrespect a person's kindness and mistake it for a weakness, you will pay,” he screamed, raising his voice and jabbing his finger at Poirier.

“I'm going to make this man pay with his life tomorrow night!” And I really mean it!

“By tomorrow night, you'll be dead in that octagon!”

Despite McGregor's terrifying pre-fight hyperbole, Poirier appeared unfazed, and when Rogan asked him what McGregor's words meant to him, he simply replied, "It means nothing – it's noise."

“Tune in tomorrow night. I appreciate all of the applause and boos. “I adore all of you.”

Poirier then paid tribute to a young man in the audience who had traveled all the way from his hometown to Las Vegas.

“I'd like to recognize a young man in the audience who is a true fighter from Lafayette, Louisiana,” he remarked.

“Keep fighting, brother, Peyton Murphy. You're a true fighter.”

Murphy, 21, has a rare kind of bone cancer, and Poirier recently assisted in raising $30,000 to assist Murphy's family with Peyton's continuous treatment.