After the boss fight with Spoiler:Ra's, the player can either exit and continue the story or head back the way they originally entered. Heading back will lead to a dead end with a locked gate. Using a remote controlled batarang on the button its connected to, Killer Croc, a villain featured in Batman: Arkham Asylum, will burst though the wall and talk to Batman. This is the only time Killer Croc appears in the main game.
Contributed by DrakeVagabond