Enchanted Fey Dragon

As reported by Wowhead in this article: Blizzard Store: Enchanted Fey Dragon and Alterac Brew Pup On Sale, Comment To Win

Blizzard unveiled their two latest additions to the Blizzard store in a special bundle--the [item=97989] and [npc=74402]!

You can purchase the [npc=74402] and [item=97989] for $30 total here. For every [npc=74402] and [item=97989]bundle or individual Alterac Brew Pup purchased now through December 31, 2013, Blizzard will donate $5 to Make-A-Wish®.

You can also buy them individually: the Brew Pup for $10 here and the mount for $25 here

Wowhead's article also provides the following information about this mount:

This mount changes color--going between blue, yellow, and red. As an added bonus, it scales based on your riding level and functions as a ground mount in no-fly zones.

The Battle.net Shop notes:

It looks good in every color

Entrusted with protecting the Emerald Dream, the Enchanted Fey Dragon absorbs magic and exudes style—with a chroma-shifting twist. Saddle up on one of these iridescent sprites and enjoy the instant street (and sky) cred that comes with being one of the last bastions of cool.

Flying carpet`s is from Tailoring, Not enchanting, the only thing enchanters have had is the Pet from cataclysm

Blizz store pet that is a similar model to the many fey drakes you see around azeroth. However these beautiful mounts change color periodically going from blue to red to yellow and back to blue (although i might have missed a color). This is the only mount that naturally shifts colors as it is out. Definitely stands out amongst all the other mounts.