>>508230545
I would count them.
And I would count them extremely slowly.
I would bring out a notepad and a pen, and tally every individual coin methodically.
I would keep them at the counter until they decided to cut the joke short and say don't bother.
I would ask them if they are sure, and then I would go to hand their money back.
And drop it all.
If you can't turn a prank on you into a prank on the prankster, you're not fit to live in Clown Town.