Conor McGregor squares off against Dustin Poirier tomorrow for UFC 257. While McGregor “retired” back in June, he is making a return to the octogon tomorrow in a rematch of his 2014 bout with Poirier. It seems as if he was just throwing a hissy fit for not getting his way last year as the Irishman returns with some staggering odds to win. Luckily for him this is not a boxing ring so hopefully we will see the McGregor of old. Until then, here are some of his best knockouts throughout the years.