The Coming Crack-Up Boom

Basically this happens after decades of inflating currency. People go through a severe adjustment in the value of money at some point near the end where the money gains in value suddenly. Prices plunge as a result but so does employment as mal-investments are liquidated. People begin to hoard cash thinking prices will continue to drop but once excess capacity has been liquidated prices begin to rise again reflecting the reduced value of currency due to the surge in the supply of money in an attempt to "fix" the economy. When the public realizes prices are not going to go down but rather, escalate rapidly, then they will liquidate their dollars as fast as they get them which is what Von Mises called the Crack-up phase of this fiat banking cycle.

There is greater detail here:

What is a "Crack-Up Boom?" Von Mises explains (with thanks to Ty Andros for reminding us):

"'This first stage of the inflationary process may last for many years. While it lasts, the prices of many goods and services are not yet adjusted to the altered money relation. There are still people in the country who have not yet become aware of the fact that they are confronted with a price revolution which will finally result in a considerable rise of all prices, although the extent of this rise will not be the same in the various commodities and services. These people still believe that prices one day will drop. Waiting for this day, they restrict their purchases and concomitantly increase their cash holdings. As long as such ideas are still held by public opinion, it is not yet too late for the government to abandon its inflationary policy.'
"But then, finally, the masses wake up. They become suddenly aware of the fact that inflation is a deliberate policy and will go on endlessly. A breakdown occurs. The crack-up boom appears. Everybody is anxious to swap his money against 'real' goods, no matter whether he needs them or not, no matter how much money he has to pay for them. Within a very short time, within a few weeks or even days, the things which were used as money are no longer used as media of exchange. They become scrap paper. Nobody wants to give away anything against them....