Rocksteady famously hid a little Easter egg in Batman: Arkham Asylum, but did it so obscurely that the studio came out and explained how to find it themselves. It hinted at Arkham City, so obviously Bat-fans would be searching high and low in that game for any sign of Rocksteady's next project. Now that Arkham Knight has been announced, the studio has explained how it started to lay the groundwork in the last game.

Game director Sefton Hill explained to Game Informer that the studio dropped two hints in Arkham City that indicated Scarecrow was still biding his time against Batman. Since a Scarecrow fear toxin attack causes a mass evacuation in Arkham Knight, it was laying the groundwork for that plot thread. Unlike the hint in the first game, though, fans found these clues pretty quickly since they knew to look for anything unusual.

The first clue was the appearance of a barge. You had to stand in one particular spot and use a particular gadget to see it, but the shipping manifest listed insects for Jonathan Crane (Scarecrow) used in his fear toxin. Hill said it only took about one day for that to appear on YouTube. "And we were like, 'How did that happen?'"

The other hint was hidden in transmissions. Three messages from Scarecrow promise he'll return, culminating in the threat that "Fear will tear Gotham to shreds." Each transmission used increasingly difficult ciphers, so Rocksteady was confident that would remain secret for longer. Not much longer, as it turns out. “I did the codes for those, and I remember talking about it with Nick the audio director and it was just like ‘No one will ever crack those codes, because they’re just ridiculous,'" Hill said. "And I think again that was like a couple of weeks and they were cracked.”

The lesson is apparently never to underestimate the power of the Internet, especially when they know you've probably hidden some sneaky bits in your game. These clues were a little less clear in hinting at a sequel, though, given that several other characters in Arkham City gave prophecies or threats. And of course, the precedent certainly means fans will pick over Arkham Knight like crazy looking for any hint of Rocksteady's next project to come.

Check out our Arkham Knight preview for more details on Batman's next visit with Gotham's rogue's gallery.