When a person (usually an African-American) begins acting out in a loud, obnoxious and unreasonable way towards others or worse, the police.
All the cop asked him for was his drivers license, then he starts going monkey
on the cop and got arrested. or;
I told that black lady we were out of the stuff she wanted to buy, so she starts yelling and screaming at everyone in the store-she really went monkey
there for a while.