The Joker Goes to School - S1.E15

At Woodrow Roosevelt High School, a vending machine gives out money. Dick Grayson is there to witness it. Batman learns the vending machines are operated by a company bought by the Joker after being released from prison. The Joker and his gang are aided by Susie, a cheerleader at the school. In the course of their investigation, Batman and Robin are captured and placed in electric chairs. If a "one armed bandit" comes up the wrong way, they'll be electrocuted.