In highschool, someone as a joke put a banana in the laptop pouch of my backpack, figuring that I'd find it later that day and wonder where it came from.

I didn't have a laptop, and I didn't use that pouch. It was a separate zipper, and was heavily padded, and I had no idea it was there. They forgot about it.

After a few days, I kept noticing a wet spot wherever I set my bag down. After a few weeks, the weird rotting look at the bottom of my bag was too much to ignore. I investigated, and the horrors that were at the bottom of that pouch are not the likes I'd speak here.