S2·E46 A Riddling Controversy

After two more robberies, the Riddler has enough money to purchase Professor Charm's Demolecularizer. He demonstrates his weapon on a park statue, then issues an ultimatum - if all criminal statutes are not rescinded within two hours, he will begin dissolving every building in Gotham City. He rigs his device to automatically fire on police headquarters if his demands are not met. The city's only hope is Batman, who believes he has a plan to counteract the device.