Ok, this happened in another school near my own, a catholic school run by priests strict to the point of unreasonable, asshole-level old school strict, they even applied corporal punishment every once in a while.

The story spread like wildfire, there were a ton and a half of cross-school friendships between that particular school and mine. This was "somewhere in Mexico", to keep it anonymous.
Strap in, it's a long story but it's a doozy.

There was this really overweight kid, he wasn't bullied or anything, he had friends and everything.
One day in the middle of class, he raised his hand - "May I be excused? I really need to go to the restroom", and the dismally unsurprising response was - "Certainly NOT! Learn to hold it in! bE a MaN!" A few minutes later, a foul stench spread across the classroom. The kid didn't say anything, he just got up and walked out, as everybody stared in a stunned silence.

Everyone in class stormed the windows from inside to see the kid as he walked across the school yard towards the restrooms, on its' own building, and locked himself inside. One classmate suddenly yelled out - "The shitter!", and within a few seconds the entire classroom joined in a loud chorus - "THE SHITTER! THE SHITTER!"

Par for the course with these sociopathic and incompetent priests, everyone knew there was no paper in the restrooms, a common occurrence.

This poor kid stayed locked inside the restroom as a teacher here and a priest there knocked on the door and attempted to negotiate. This went on for a couple of hours, until the kid's brother arrived at school, walked across the yards, carrying a fresh change of clothes, knocked on the restroom door and was let inside.

By this point, everything in school was at a standstill, every single student in every single classroom was glued to the windows, staring in silence. You could hear a pin drop. Then the door opened, kid and his brother walked out, and headed for the school exit.

Then one kid shouted - "The shitter!", and now the ENTIRE school, from every classroom window, joined in the chorus - "THE SHITTER! THE SHITTER!!!"

The poor kid never did return, he transferred to another school. On the one hand, surely out of shame, but on the other, because the casual, mindless and indifferent cruelty the goddamned priests imposed on children. In a more empathetic, humane school, this would have not happened.

Here's the cool epilogue - when this kid attended high school some years later, nobody bothered him about the incident, he had his own band of friends, went to parties and everything. When the story was told, the emphasis was on the asshole priests. That's a comforting thought.