Rapper XXXTentacion, whose real name is Jahseh Onfroy, was knocked out by an unidentified man who ran on stage during a show at the Observatory North Park theater in San Diego on June 7 (video below).
TMZ reports that security guards rushed the stage and beat the unidentified assailant, but the drama wasn't over as the incident swelled into a brawl.
San Diego Police Sgt. Jordan Wells said a 19-year-old victim was stabbed, notes KSWB.
According to Officer Billy Hernandez, there have not been any arrests made yet.
Sources with law enforcement told TMZ that the stabbing happened backstage.
The rapper had to be carried off stage, and was unconscious for about two minutes, according to one of his managers.
After he was attacked on stage, XXX's voice kept playing, which was said to be a vocal track.
XXX returned to the stage a few minutes later to show everyone that he was okay, reports Heavy.com.
Some of XXX's fans blamed another rapper, Rob Stone, for the violence and chanted his name.
Police are reportedly trying to get a statement from XXX, who tweeted a video in which he said security and the venue had allowed the attack and inferred they knew it was going to happen.
XXX wrote a similar assertion on Twitter: "security and venue set me up, I got sucker punched and knocked out, it is what it is... next time make sure you kill me so I can't talk s***."
XXL magazine reports that XXX had had a rivalry with Rob Stone, who jumped XXX's tour buddy, Ski Mask The Slump God, during a performance earlier this year.
According to the magazine, Stone hails from San Diego, which may have been a dangerous location for XXX's performance, but there is no evidence that Stone was behind the attack.
The New York Daily News reports that XXX is accused of physically assaulting his pregnant girlfriend, forcibly confining her and attempting to bribe the victim to not testify against him. XXX has pleaded not guilty, and has a trial hearing on June 26.
According to Heavy.com, XXX's best known song, "Look At Me!," peaked at number 34 on the Billboard charts, but he boasts an impressive following on his SoundCloud page with over 976,000 fans and more than 400 million plays.
XXX has also had some drama with Drake over allegedly ripped-off music.
XXX is scheduled to continue his "Revenge" tour with an appearance in Santa Ana, California, on June 8.