Reven
Source: In-Game Shop. The game's afoot. Except when it is time to nap. Afterwards though, it's game on! Beast type. Because he can combo Crouch and then Nap, even though he's quite expensive for a battle pet at $20, I call this one worth it, especially since he's speedy enough to actually use pounce.
Reven is a vanity fox pet available as part of a limited-edition $20 charity bundle in the in-game shop, with 100% of proceeds going to CureDuchenne in honor of Norwegian World of Warcraft player Mats "Ibelin" Steen.
Guide awaiting review
Purchase Reven from Shop
Head to the in-game shop and purchase the $20 limited-edition bundle, which includes Reven and the 
Reven's Comfy Carrier back transmog. Per the store page's fine print, this bundle will not return once it is no longer available.
Summon and Enjoy Reven
Once redeemed, summon Reven to see the fox wearing a Sherlock Holmes-style deerstalker hat; it idles by sniffing the ground and occasionally sitting to scratch itself with a hind leg. Note that the Reven's Comfy Carrier backpack always displays a sleeping copy of the pet, but Reven will not physically jump into or interact with the backpack when summoned.
Tips
The Reven's Comfy Carrier back transmog and Reven pet are two separate items included in the bundle and have no in-game interaction with each other.
