At primary school, me and my friend (who was the WORST influence, my god) snuck back into our classroom during lunch break and poured an entire tub of fish food into the fish tank. No one noticed and the next day every single fish in the tank was dead due to overeating. One of our classmates went home, she was traumatised.
I've gotten away with a lot worse but I refuse to post cause my ass would probably get arrested