A massive fight broke out at an AAU basketball game over the weekend ... when a referee was attacked by several people -- including a player -- after appearing to throw a punch at a coach during a heated in-game altercation.
The violent incident happened during the Hardwood Classic X RecruitLook Summer Finale in Kansas City ... after a coach appeared to lose it over a technical foul call.
In the video, the coach -- wearing blue shorts and a grey shirt -- gets in the ref's face after hearing the whistle .