Conor McGregor has been mostly great for the UFC during his nearly five years as part of the promotion. On Thursday, though, he undid every bit of goodwill he built up in becoming MMA’s biggest star.

What happened in the bowels of the Barclays Center in Brooklyn on Thursday was no less than organized crime.

McGregor and about 20 of what best can be described as hoodlums along with him created a chaotic scene following the media day for UFC 223. McGregor can be seen in video footage hurling a dolly against the window of a bus in which fighters, including lightweight Khabib Nurmagomedov, were waiting to be taken back to their hotel.

Thursday’s incident at UFC media day did incalculable damage to Conor McGregor’s reputation, as well as that of the UFC. (AP) More

McGregor also flung a crowd barrier at the bus, while his so-called friends did the same. McGregor turned himself into police later in the night and has been charged with three counts of assault and one count of criminal mischief.

The incident did incalculable damage to McGregor’s reputation, as well as that of the UFC. But there was other serious damage inflicted, as well. Two fighters, Alex Caceres and McGregor teammate Artem Lobov, lost a fight. Another, Michael Chiesa, who was cut by broken glass caused by things thrown at the bus window, needed medical attention and his fight with Anthony Pettis is in jeopardy.

This could easily have been a far more significant incident, and it’s hardly a leap to think that there could have been serious injuries.

McGregor has been the unofficial face of MMA for at least several years. He’s a terrific fighter, a brilliant self-promoter and a witty, media savvy businessman who has built himself into a mini-empire.

He has, however, put his fight career in peril. Imagine what might occur at an athletic commission meeting if the UFC were to try to pit McGregor against someone he sees as a rival, such as Nurmagomedov or Nate Diaz. It is hardly a guarantee that he would be licensed in the U.S.

And he’s put the UFC in a position it didn’t want to be in. He’s the biggest star and its most bankable athlete, but the UFC has to take disciplinary action against him beyond whatever might happen to him criminally.

No one knows for sure what set McGregor off, though being stripped of his belt and a confrontation in the fighter hotel Tuesday between Lobov and Nurmagomedov are likely a big part of it.

McGregor put out a vile tweet early Thursday, saying the UFC wouldn’t strip him of the title. McGregor has never defended a title in the UFC, despite winning featherweight and lightweight titles. He stopped Eddie Alvarez in New York in November 2016, and by Saturday, when Nurmagomedov and Max Holloway step into the cage at UFC 223 at the Barclays Center for the main event, it will have been 512 days since McGregor won the title.

It’s manifestly unfair to the fighters in his division, as well as the fans, that there hasn’t been a championship fight since he defeated Alvarez. He went 337 days between winning the featherweight title from Jose Aldo at UFC 194 until being stripped of the featherweight belt when he defeated Alvarez.

If anything, the UFC was pitifully slow in taking the belt from him. It allowed him to fight boxer Floyd Mayweather and make a nine-figure payday in 2017, and didn’t strip him. He was putting a stranglehold on the business, both for the UFC and for his peers in the lightweight division.

Fighters make far more money, directly through purses and indirectly through sponsorship and personal appearances, when they’re a champion. And so McGregor was costing many of his fellow fighters a chance at life-altering money themselves.

More troubling, though, is the thought that he flew to Brooklyn from Ireland to confront Nurmagomedov as a result of a hotel confrontation with his teammate. That makes his out-of-control actions Thursday premeditated, when he knew or should have known that his actions could cause serious damage.

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