What's the weirdest unsolved mystery you've ever been PERSONALLY involved with? Not something you read on the internet, but something that happened to you or a friend, be it a baffling unsolved crime or just something that seems inexplicable, even if it's low stakes?

When my brother was a child, he was riding on a tractor with my grandfather, my brother holding a toy. He dropped the toy and they immediately stopped to retrieve it, only it had apparently vanished from the universe. They spent an hour looking for it, the thing was just... gone.

I know it's low stakes,as stories go, but there was no place for this (large!) toy to go, it should have fallen right to the grass and they immediately stopped to get it. It shouldn't have been ten feet away. But in the next 20 years of living there, no one ever found it.

As for me, a few years ago I had a few hundred dollars vanish from my desk drawer (emergency cash in case of a disaster that cuts off ATMs). The only person who had access to the room is such an unlikely suspect that I'd sooner believe I'd started sleepwalking and did it myself.

I don't want to sound naive - I mean this person had no reason to even look for the money in that spot & almost no opportunity. They're a well-known contractor with an impeccable reputation who was already getting paid much more. I half think I just spent it and forgot?