Sometimes, the makers of Gotham just can't help themselves. They latch onto an idea, a stupid little joke, and they have to repeat it over and over. That's the case for, say, everybody always saying that Oswald Cobblepot has something of a penguin about him (foreshadowing his future supervillain name) or all those Joker-related red herrings. Then there's Fledermaus. In the first season's twentieth episode, Charity Case, Wayne Enterprises holds a charity ball that takes place at somewhere called the Fledermaus. Then there's a brief shot of a newspaper on the ground in next episode The Anvil And The Hammer, which is called Fledermaus Chronicles. Fledermaus, for those who aren't fluent in German/using Google Translate, is the German word for bat. It literally translates as flying mouse. How about that for an obscure reference as foreshadowing? Of course, it could be a double-edged Easter Egg, since Die Fledermaus is also a famous opera about revenge, which these episodes are all about.