Machine Gun Kelly's goons ganged up on a guy, and beat the hell outta him -- on video -- and now the victim's suing the rapper, claiming he ordered the attack.
We broke the story ... Gabriel "G-Rod" Rodriguez confronted MGK back in September at an Atlanta restaurant and called him a "p***y" because he was pissed about Kelly's beef with Eminem.
Later in the evening at a Hampton Inn, video footage shows G-Rod getting jumped and viciously body slammed, kicked and punched by a bunch of dudes allegedly in MGK's crew. At least 3 of the individuals were ID'd and charged with misdemeanor battery, but cops said MGK was in the clear because he wasn't a part of it.
G-Rod's not letting him get off that easy, though ... and filed suit against the rapper and the 3 other dudes in his crew for battery. According to the docs ... Rodriguez claims Kelly instructed the bodyguards to attack him, and he's suffered serious injuries and medical expenses.
G-Rod's also suing the hotel for negligence in the incident.
As we told you, G-Rod's attorney, Blake Dolman, threatened to pursue legal action if MGK didn't cut his client a check. Guess that never happened.
Dolman tells us ... "Mr. Rodriguez looks forward to his day in court and holding those responsible for this vicious and cowardly attack fully responsible for their actions."
MGK's manager tells TMZ ... "it's a bogus lawsuit and MGK is not liable for what happened."