Conor McGregor and Nate Diaz didn't seem to actually have too much of a personal rivalry between themselves ahead of their UFC 202 rematch.
The Irishman and American always seemed to sort of respect each other, but that thought was quashed completely earlier at a truly insane press conference ahead of their fight that saw bottles and cans go flying.
And the bad blood carried over into last night, as the weigh-in proved to be a particularly spicy affair for all involved.
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When the two fighters went in for the traditional face-off, a lot of words were said back and forth, each fighter trying to goad the other into making a move.
Diaz seemed to fake a punch and caused McGregor to flinch, which was never going to end well. That's when it got rowdy and the two had to be separated.
You can watch the amazing incident here, thanks to UFC on Fox's Facebook page.
"You should have killed me when you had the chance because now I'm back and I'm gonna kill you and your whole f****** team," McGregor shouted at Diaz following the stand-off, before he stormed off.
Diaz made sure to get his own words off.
"I train always hard to kill," the American said. 'He's already dead from the last time. This is a new fight so it's kill or be killed again."
Diaz then walked off, before throwing one of his own shirts - that had been kept in his shorts - at McGregor's teammates and family in the front row.
This is going to be explosive.