Kim Kardashians Brother Robert Gets KNOCKED OUT In A Charity Boxing Match

The Kardashian family volunteered to take part in a charity boxing match--but the fun stops when the fight takes a turn for the worst.

According to Kim, her brother Rob was fighting against a dude "at least 25 lbs heavier than him" -- and the guy punched Rob's face while he was trying to fix his mask, knocking him to the floor.

The fight lasted a whopping 1:15 after that -- and Kim says Rob was taken to the hospital with a concussion.