The Flat 1916 Quarter is a damaged coin (or former coin) owned by Scrooge McDuck.
The Flat 1916 Quarter was once an ordinary 1916 quarter owned by Donald Duck. After paying the coin to Scrooge McDuck to settle a debt, Scrooge gave Donald a Balonian nickel as change, a coin which he believed was worthless, but was in fact worth five dollars. To get revenge for this loss, Scrooge decided to make the quarter which Donald payed with the rarest coin in the world, so that he could sell it and come out on top. Buying up every other 1916 quarter in the world, Scrooge sunk them into the ocean, rocketing the worth of the quarter to ten skyrillion dollars.
Unfortunately for Scrooge, the coin was lost, and traveled across Duckburg, chased by Scrooge all the way, before it stopped in the path of a steamroller and was rolled flat, rendering it worthless. Scrooge was thus forced to journey to the bottom of the sea and retrieve another 1916 quarter, which he succeeded at doing, although not without considerable effort. Although the original quarter was no longer valuable, Scrooge kept it nonetheless, in the artifact storage area of his Money Bin.