Brianna LaPaglia & Mark Estes Face Off in Muddy Brawl on 'Special Forces'

There's no love lost between Brianna "Chickenfry" LaPaglia and Montana Boy Mark Estes ... at least not on "Special Forces: World’s Toughest Test"!

In an exclusive preview clip obtained by TMZ, the Barstool Sports star goes full beast mode on the TikTok hunk during one of the show's most brutal challenges, "Murderball." The wild footage shows Brianna sprinting across the mud before delivering a sharp kick straight to Mark's stomach, sending both of them crashing into the dirt as they wrestle for control of the ball like total warriors.

In addition to the muddy mayhem, the remaining recruits also take on the nerve-racking "Postman’s Walk" ... a 165-foot rope bridge suspended 200 feet above a canyon floor, which they have just 10 minutes to cross.

It's all part of the military-style competition where celebrities are pushed to their physical and mental limits ... and Brianna's proving she's not afraid to kick it up a notch -- literally.

On "Special Forces," it's not just about who's toughest ... it's about who's willing to get down and dirty to prove it!