GSP vs. Bisping: Threats, Cussing, Insults In Backstage Standoff

Things got even crazier than we thought between GSP and Michael Bisping -- with both men threatening to knock the other out during a crazy heated showdown backstage at a UFC 217 media event.

The guys had just wrapped up a formal news conference in Toronto -- when Bisping confronted GSP backstage and shouted at him for pushing him during the event.

GSP fired back, "F*ck off man ... I will break you."

At one point, Bisping faked like he was going to throw a punch -- GSP didn't even flinch.

They continued to cuss and threaten each other for a good 90 seconds before Bisping walked away.