Rocksteady's Batman: Arkham series is filled with Easter eggs. Many of the game's Riddler challenges are based on finding references in the environment to various Batman and DC characters, but there are plenty of other, more well-hidden Easter eggs.

Batman: Arkham Knight is no exception. Players have already gone over the game with a fine tooth comb, finding all of the various secrets the game has in store. The game's first major DLC, A Matter of Family, is out now for Batman: Arkham Knight season pass holders, and that means a whole new environment that players can scan for secrets.

Like this major Easter egg, for example. As YouTuber Dribbiz shows in the video below, players of the Batgirl DLC can discover a familiar Justice League villain in a room at the other end of a hidden ventilation duct. The room contains two liquid-filled tanks and a number of pipes. Housed within one of those tanks is what appears to be a giant starfish.

Casual fans will likely find the inclusion of a giant starfish strange, but hardcore DC Comic fans will instantly recognize the character as none other than Starro — a massive alien starfish and the first villain the Justice League of America faced way back in 1960. It took the combined might of Green Lantern, Wonder Woman, the Flash, Aquaman and Martian Manhunter to bring it to justice.

What exactly the character is doing in Gotham City is unknown. Might Rocksteady be teasing the idea of a Justice League game? There are numerous other DC universe characters outside of Batman's rogue's gallery who make cameos or appearances in Arkham Knight, such as Lex Luthor and Deathstroke. The fact that Rocksteady has included such an important character in Justice League history as an Easter egg – when the developer has thousands of other references to choose from – might say something about the studio's future game plans.

Or it could mean nothing at all, and Rocksteady just thought it would be fun to include a giant starfish from outer space. Regardless, we can all hope Rocksteady won't be leaving the DC universe behind after Arkham Knight. A Superman or Justice League game from the studio would be a dream come true.

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