The first thing that came to mind wasn't actually in school, it was at home, but it was when I had just got home from school so I hope it's okay.
I was eating nutella from the jar, with a spoon. Like a goblin. I had a huge amount on my spoon. Suddenly, the front door opens and in my embarrassment for eating this large quantity of hazelnut sugar, I quickly shoved the jar away in the cupboard, and snuck by my parents with the spoon behind my back.
Uh oh. I was planning on eating the nutella in my room, off the spoon, but I realised it was far too much nutella. Maybe I lost my appetite. Either way, the only recourse in my mind was to dump the contents of the spoon down the toilet, and stash the spoon to be returned at a later date.
Not only did the nutella not flush, but I also didn't notice that it hadn't flushed, leaving a sight that I'm sure we can all imagine. My parents were furious, we actually had guests so they were livid that they could have seen this. They pulled me to one side, were basically yelling at me: "We're not mad you did it, we're mad you're lying to us about it."
I didn't know what to do. I just kept telling the truth. I was eating nutella and didn't want to get into trouble for the gigantic spoonful so I tried to hide it. Resulting in a stalemate.
Anyway, I'm not sure they actually remember this happening, but it was quite traumatic for me because I was otherwise quite a good boy.
Unironically a sack of potatoes should be an S tier ranked grocery. They are extremely versatile, can be as healthy or as unhealthy as you want them to be, make some incredible delicious things, and are also one of the cheapest things by weight.