oh wow, that's amazing, I am laughing out loud, please excuse me. XDI have a story... oh boy.
This happened the night I got my first proper fishtanks - a 12L nano.
I came home and unpacked everything for the fish tank. I followed a video online that said you need soil underneath the sand and you also gotta wash sand before you put into the tank so I got soil, sterilised it (in the oven) and put it into the tank. Next I cleaned the sand and tried to put it into the tank but it was all wet and wouldn't come out of the bottle I tried to half way clean it in. So I then used dry unwashed sand over the soil and started to fill it up with water. I messed up filling it, and poured in water too fast so the soil and sand went everywhere in this awful brown mixture. I let it settle and then added more sand on top to fix it. It didn't work. After using about 3kg of sand and a lot of water changing to try clear it up, I decided this ain't going to work. So I went into the bathroom and thought that it would be able to go down the sink. Yeah. So I upturned the tank and GUESS WHAT? The sink blocked the heck up. Panicking, I spent the next hour scooping mud and sand out of the sink and trying to unblock it using my hands as a plunger - mainly because I could not find said plunger. It was everywhere and I filled up two basins with mud and sand and water. I was really panicking and decided that I'd siphon out the sand myself (ew) So I got several straws and tried my best to suck the sand and mud out of the drain myself. (Brilliant idea, I know.) After an hour of this mixed with repeated gagging and spitting I gave up and crying, went down stairs and told my parents. Long story short I had to have a crash course in plumbing with dad to fix the sink because of my remarkable twatery. So yeah. Don't put sand down the sink. EVER.