Of course there were going to be daft outer-space references. One of the game's Achievements asks you to go to the Moon and explore, until you find a shiny silver Batman statue (why wouldn't there be one on the Moon?). In the same area, dancing around the statue in fact, you'll also find a small herd of cows, obviously. The cows are all wearing Batman like capes - an obvious reference to the Batman Inc-created Bat-Cow who was Robin's pet (and the inspiration behind his vegetarianism) in Grant Morrison's 2012 run. There's clearly no reason for there to be three Bat-Cows however, but finding them will unlock the Achievement called "Hey Diddle Diddle!"
