Once when I was in primary school, I had a birthday party at my house. There was one specific cardboard box I used to put all of the chocolates inside of (for prizes during the party). After the party, we decided that the box took up too much space in the house, so we stored the chocolates somewhere else and threw away our box.

Approximately two months later I'm at school and it's home time. I walked home (the school was close to my house) then realised that I forgot to take back my instrument (since we had instrument programs at our school). I walk back and when I entered the school again I found something rather peculiar. It was a piece of cardboard, with the exact same messy handwriting as the box I used for my birthday party then.

I realised that a small part of the cardboard box I threw away months ago had somehow made its way into the school two months later. This still boggles my mind to this day, to think how this could've happened, how it would've taken so long, how I would never have noticed this if I remembered to bring back my instrument that day, etc.

I know it's not anything incredible like what others have commented about, but it was such a mysterious phenomenon that I decided I'd share it here.

TL;DR: I threw away a cardboard box and found part of it on the floor at my school two months later.