Granted; you now have over 18 quintillion US dollars. This unprecedented and literally magical addition to the economy causes the US dollar to collapse, plunging the world into economic chaos. Your dollars are now basically worthless (as are everyone else's) because if I know anything about economics, that's definitely what would happen if $18,446,744,073,709,551,615 suddenly appeared from nowhere.
I wish for my back to stop hurting.