Rampage Jackson Will S**t His Pants

Bring some baby wipes to tomorrow's Triller media event ... 'cause Shannon Briggs tells TMZ Sports Rampage Jackson will literally poop his pants when he lays eyes on Cannon.

We talked to the 49-year-old former heavyweight champ, acting as the captain (across from Quinton) for Triller's upcoming Triad Combat event on Nov. 27 ... and asked Briggs about coming face-to-face with his rival.

"We're gonna see each other, there's a press conference Wednesday, the weigh-ins Friday and the fights Saturday. I'm looking forward to it champ. When I look at him in his face and I tell him 'lets go champ', we're gonna see. I think personally he gonna defecate on himself. I think he gonna defecate, but he…