This is really, really gross and this guy's response is completely appropriate.

Two amateur MMA fighters were in the middle of their fight, and one of the fighters had his face next to his opponent's butt because of some hold he had locked in. Who knows if he did it on purpose or not, but the fighter farted right into his opponent's face, which caused the opponent to barf on the mat.

Who can blame the guy for barfing on the mat? It's always gross just to smell a fart, but to get one right in the face would get to anyone. His face was so close to the guy's butt that he probably tasted it too, which will make people want to barf just thinking about it. Hopefully no one tries to repeat this tactic because most people would probably believe that this is just as bad as a low blow.