Girls Get In Wild Porta-Potty Brawl At Morgan Wallen Show Inside MLB Stadium

Several girls got so upset with each other while in line for a porta potty at Morgan Wallen's show Wednesday night ... they straight up beat the snot out of each other -- and the wild fight was all captured on video.

The incident happened inside the Pittsburgh Pirates' stadium, PNC Park ... and while it's unclear what sparked the melee -- it appeared a dispute over who could use one of the toilets is what set everyone off.

You can see in the footage, two girls were arguing next to a porta-potty ... before they began pushing and shoving each other.

Eventually, the two's tussle spilled into one of the open Johns ... and despite the gross conditions, they still continued to pound on each other.

One of the girls' apparent acquaintances then came in to break it up -- and that's when things turned way more violent.

The girl in the blue romper and white cowboy boots pulled one of the combatants out by her hair and threw punches. She then swung on another girl, before kicking her.

Ultimately, cooler heads prevailed.