Any Dragon Battle MMO's Out There?

I been wondering this for many two years off and one, but, is there any dragon battle MMO's out there? Like you control a dragon and you fight against another player's dragon. You don't have riders on them because that would be much of a hassle. I'm thinking of a third or first person shooter style but with dragons. Anyways, I'm done with my ramble, but does it exist on any OS?

I had this also on Ubuntu Forums: http://ubuntuforums.org/showthread.php?t=1519715