Knock, knock. Who’s there? Karma…

Rapper XXXTentacion released a controversial video for his singles, “Look at Me” and “Riot,” on Tuesday, which featured the hanging of a young white child, but he wasn’t able to do much against a grown man.

Video from June showed the raper XXXTentacion got sucker punched onstage and knocked out cold during his show in San Diego … which turned into an all-out brawl that left one person stabbed.

Go HERE for black conservative Terrence Williams take on the horrific video showing a white kid being hung in front of a black kid.

The video of the attack is insane — XXX was up on the mic performing Wednesday night when the attacker socked him out of nowhere. Security scrambled and beat the piss out of the unidentified puncher.

While all the attention was on the nasty rapper who got knocked out, the person who cold-cocked him on stage was pummeled by security. Is it part of the security detail’s job to mob beat anyone who harms the performer they’ve been hired to protect, or is it their job to capture and detain him until the proper authorities have arrived? Let’s hope this guy who jumped on stage and gave this disgusting rapper a little dose of karma has a good lawyer because he needs to sue those security guards for using excessive force…

XX was eventually carried offstage. One of his tour managers tells us he was unconscious for at least 2 minutes. We’re also told XXX and his camp believe the attacker was hiding backstage.

Cops say another fight broke out later in the parking lot as well. Fans at the venue seemed to blame rapper Rob Stone for the melee — they chanted his name as soon as the fight started, but it’s unclear if he’s really involved. –Conservative Fighters