Police say they plan to charge US YouTuber Kai Cenat after a video games console giveaway event he organised sparked mayhem in New York.
Thousands of people rampaged through Union Square in anticipation of free PlayStation 5 devices, hurling bottles, stones and tins of paint.
Mr Cenat could be charged with multiple counts of inciting a riot and unlawful assembly.
Police say they made more than 60 arrests.
People first gathered at about 13:00 local time (17:00 GMT) after Mr Cenat posted on social media - where he has more than 10 million followers and subscribers - that he would be handing out 300 PlayStations.
By 15:00, hundreds had piled on to streets surrounding one of New York's busiest train stops.
They climbed cars and the train station entrance's roof and threw bottles at responding police officers.
During a livestream inside a vehicle near Union Square as the disorder was unfolding, Mr Cenat said: "They're throwing tear gas out there.
"We're not going to do nothing until it's safe. Everybody for themselves, because it's a war out there man."
Mr Cenat was taken into police custody at around 17:00. The crowd was finally dispersed about an hour later.
According to a CBS affiliate, Mr Cenat did not have a permit for the event, which was reportedly a collaboration with Bronx YouTube star Fanum.
NYPD chief of department Jeffrey Maddrey said: "We have encountered things like this before, but never to this level of dangerousness, where young people would not listen to our commands."
He added: "You had people walking around with shovels, axes and other tools from the construction trade.
"In addition, individuals were also lighting fireworks. They were throwing them towards police and they were throwing them at each other."
Mr Cenat made headlines in March after he broke the record for attracting the most Twitch subscribers by reaching 300,000.
Twitch is a livestreaming platform, where people typically play video games while chatting to viewers.
In the build-up to breaking the record, Mr Cenat launched a round-the-clock drive to boost his subscribers - chatting, gaming and interviewing guests, as well as sleeping, all on camera - for 30 days.
Requiring a permit to assemble feels like a way to undermine the right to peacefully assemble.
But in this case they had no reason to think their permit might be denied - although that permit should be denied if the police can't assign officers to crowd control; it should be denied if the road is a major artery for a nearby hospital etc. - the point is you get a permit to start a conversation and get to know if the assembly is a worthwhile idea.