I'm not sure it even exists anymore. It doesn't come up on the Armory.

Maybe the amount of pets you exclude effect it too? (Not sure though)

Lil' Deathwing is my go-to pet for just about every battle! He's very powerful in most situations. The most useful skill will be his Tail Sweep ability, the reason for this is because most Battle Pet Tamers you come across will have faster pets than yours, and the Tail Sweep will do additional dama...

Mine vanished too! I was wondering if it was something I had screwed up... But good to know I'm not the only one! Won't be worried about it now .

Yeah, I just came across the vendor today and was disappointed to know that the stone is only to upgrade to Uncommon.

I've gotten one each day through dailies so far, 1 humanoid, 1 aquatic, & 1 dragonkin. Yesterday I got a critter stone to drop off of a rare I captured in Uldum. I'd say it's been going pretty good.

Yeah, this ones is pretty rough. I've only ever gotten to 3/5.