Technically not a cat. Looks like a cat. Very dangerous. Be glad you haven't encountered one, yet.
I'm not surprised you didn't know about it. It was pretty classified. I think it was Fury's first encounter, too.
What happened when he used them? shit I was trying to track him down before I was sucked here. I got a message from Fury on his pager-thing. I'm going to take a wild guess that this was what it was about.