Former UFC champion Conor McGregor knocks down the Miami Heat mascot during a promotion in a game four NBA Finals timeout.

McGregor was at the game to promote a new painkiller and was booed by crowds in Miami when he was unveiled. The Miami Heat mascot, known as Burnie, took to the field and challenged McGregor to a not-so-serious match – then McGregor immediately struck out.

McGregor savagely knocked the mascot down with a left hook and then punched him in the face as well.

Following the incident, The Athletic wrote: “The MMA fighter’s punch was so severe that medical treatment was required. The person in the costume was taken to the hospital.”

McGregor’s surprisingly violent action was criticized by many fans as far too aggressive. It remains to be seen whether proceedings will now be instituted against McGregor.

The Heat lost the game to the Denver Nuggets and are 3-1 down in the series.