EXCLUSIVERapper YG started the chaotic water bottle melee that abruptly ended his concert ... and he did it to cover up the fact that he couldn't sing.
YG lost his voice 2 songs into his performance ... that's what a rep for the promoters tell TMZ. The promoters say the rapper first tried to get his DJ to pump up the volume to mask his voice, but when that didn't work he resorted to throwing water bottles at the crowd ... which predictably turned bad.
Apparently YG wasn't sure the bottle would do the trick, so he jumped off stage and punched a fan in the face ... and that's when all hell broke loose.
The promoter tells us the club is now in danger of losing its license. We're told the club may take legal action against the rapper.
We reached out to YG's camp for comment ... so far, no word back.