Riddler to Batman

When a bat cannot see and from his cave he flees, to try and save Gotham from the dark, against a villain's bite that is meaner than his bark. You have but a day to solve my riddle in the perfect way.
Go ahead and try to spring my trap, if you succeed I will happily clap. However if the bat should fail, then the Riddler will prevail and Gotham shall be broke as I will laugh at Batman for not foiling my joke. Haha!