BROOKLYN, N.Y. – Conor McGregor arrived for UFC 223 fight week today, and things got out of hand quickly.

The UFC lightweight champion, for now at least, made a surprise appearance following UFC 223 media day at Barclays Center in Brooklyn, N.Y. McGregor (21-3 MMA, 9-1 UFC) was seen briefly arriving at the venue before rushing into an elevator with his team.

That led to some disturbing footage caught on video in which McGregor and members of his team can be seen vandalizing a bus carrying fighters who were set to be transported to the host hotel.

Michael Chiesa was injured with a laceration to his forehead as a result of the chaos and can be heard on video moments afterward: “Am I cut bad? I don’t want to touch my face.”

Chiesa’s coach, Rick Little, told MMAjunkie that Chiesa was “cut up” from shattered glass. Little, who was on the bus, also described what happened.

“Conor went bananas and put a beating on the van that we were in looking for Khabib,” Little said. “A million security guards had to restrain him. Mike’s cut up now. He’s got marks on him, for sure. I don’t think too serious. Everything happened so fast, it was just like we got jumped.”

McGregor apparently fled the scene with his crew afterward.

MMAFighting.com reporter Ariel Helwani reported that UFC President Dana White was at the scene talking to police.

McGregor’s arrival for UFC 223 likely is based around his desire to support SBG Ireland teammate Artem Lobov (13-14-1 MMA, 2-4 UFC), who fights Alex Caceres (13-11 MMA, 8-9 UFC) on the card. He also provides some additional intrigue to the main event title fight, where Khabib Nurmagomedov (25-0 MMA, 9-0 UFC) and Max Holloway (19-3 MMA, 15-3 UFC) are scheduled to fight for the 155-pound title.

UFC 223 will take place at Barclays Center. The main card airs on pay-per-view following prelims on FS1 and UFC Fight Pass.

For more on UFC 223, check out the UFC Rumors section of the site.