This might not be credible enough to label as "news," but it's definitely an interesting rumor. Christopher Nolan's third Batman film is pretty much a mystery at this point; all we really know is that it's happening, and at least some of will be shot in New Orleans. Most people have assumed the locale was picked because of the generous tax credit given by the state of Louisiana; but there's buzz growing that the location may actually play a significant role in the story.
If Killer Croc came to mind when you read that, you're on the right track.
A few days ago, comics writer Mark Millar tweeted, "Oh, wait. Con gossip: I know who the villain(s) are in Batman 3 and the big scene outside Gotham sounds awesome. Totally timely locale."
Obviously he didn't just come out and say it, but can you think of another prominent Batman villain that would fit in so well with a Louisiana location? Millar followed that up with a tweet reading, "One of the villains is from my favourite childhood run on the character. Again, very unexpected."
Millar would've been about 13 when the character of Killer Croc first appeared, so it's debatable but still totally possible that Croc would fit into that timeframe. Regardless, this rumor really only has Mark Millar to go on, so it comes down to whether or not you believe him. It's still an interesting possibility though, and one worth discussing.
If you're unfamiliar with Killer Croc the Batman Wiki describes him as,
A former crocodile wrestler turned into a criminal deformed by a birth defect. He has low intelligence but great strength, as well as crocodilian abilities, such as a keen sense of smell and the ability to hold his breath underwater for long periods of time.
Killer Croc has been a central villain in Batman comics as well as in several different incarnations of the Batman animated series, but he’s never before been a part of the movies.