A little pet I picked up in Uldaman
Seriously, he just spawned when we were half way to him on a boss run, in the middle of the tunnels - before even the temple where he should be. We couldn't hit him and he followed me around (always about six feet behind) - even to the instance entrance which you can see in this shot. If i left or logged out, he'd wait patiently for my return - when he'd start following me around again.
Very, very odd.