The Chuck E. Cheese restaurant in Boynton Beach, Fla. where the brawl broke out during a child’s birthday party.

Chaos erupted at a Chuck E. Cheese restaurant in Boynton Beach, Fla. when an 18-man brawl broke out during a young boy’s birthday party.

Saturday’s battle allegedly began when two men “exchanged words” in the restaurant’s bathroom.

Within minutes, all hell broke loose — with men from other birthday parties clashing in the dining room and trampling on the boy’s grandmother.

Staff managed to throw the fighters off the premises.

But they drove to a nearby street to continue the ruckus, which ended with a man being shot.

Three people — Briana Walker, Robert Thompson and Alfred Peoples — were arrested on drug charges and defrauding an innkeeper after allegedly fleeing without paying the $300 bill.

Walker is the boy’s mother, reports WPBF, and was found to have part of a Xanax pill and a small amount of marijuana in her purse when arrested.

Someone on her side of the car had also thrown out packages containing marijuana, Xanax, crack cocaine and morphine, police added.

Investigators, who found empty vodka bottles hidden in a diaper bag when searching the scene, say the gunman remains at large and that his victim’s injuries are not life threatening.