20. Penguin's Clean Sweep

The Penguin taints the ink at the U.S. Mint with Lygerian Sleeping Sickness. As word of the infected money gets out, citizens of Gotham City empty their cash right onto the streets - and into Penguin's pockets. But when Bruce Wayne spreads word of the infected bills worldwide, the Penguin realizes his ill-gotten gain is worthless and threatens a more devilish plot if the warning is not retracted.