An imperfection in the surface of a rental car that the rental agency says is too small to worry about, which later becomes an imperfection that you are responsible for because the imperfection has magically grown since the car left the lot.
The scam du jour with the (car rental) near me involved being charged for a pre-existing scratch. When I mentioned it when I picked up the car, they said it wasn't large enough to warrant notation. Fair enough.
Miraculously, however, when I returned it, the same exact ding (which didn't grow, it wasn't a Chia ding) now warranted a claim to be filed against me. Every time I challenged the guy on it, he pulled out this inane little plastic device and held it up to the ding. In a rare moment of losing my cool I grabbed his stupid "my first ruler" device and held it up to the dude's head and told him he qualified as a certified ding-dong and then I snapped it in half.