It wasn't one that I'd ever seen before, and certainly not mine. Nothing taken or damaged, no note, just a random empty laundry basket placed on the back seat.
This was in my office parking lot, and I can see the truck from my office window all day. Everyone that I could even conceive of somehow being able to orchestrate this has been thoroughly interrogated.
Very bizarre, still no answer to this day. But, on the plus side we do use the laundry basket even though it doesn't match the others.
When and if I get to heaven, it will be the very first thing I do to go ask for the security footage on that day.