S2·E45 Batman's Anniversary

During a party for Batman's crime-fighting anniversary, the Riddler appears and nabs a golden calf filled with money for charity. His next target is the Gotham City Bank, which he floods for an underwater robbery. Although Batman and Robin try to stop him, the villain makes a clean getaway, leaving only a final riddle that stumps the Caped Crusaders. They discover all too late that his next move is an attempt to destroy them, this time with deadly quicksand disguised as strawberry icing atop a giant cake.