Spectral Tiger Cub
Source: Trading Card Game. Affectionate and curious, these kittens seem to find the most peculiar hiding places. Magic type. TCG means "Trading Card Game" it's a redeemable loot card that you can get from the card packs.
The 
Spectral Tiger Cub is a battle pet obtained from the Scourgewar TCG expansion loot card, the Spectral Kitten, found at a drop rate of approximately 1 in every 363 booster packs.
Guide awaiting review
Obtain the Scourgewar Loot Card
The Spectral Kitten loot card is found inside Scourgewar booster packs. Booster boxes contain 24 packs and historically cost around $65 USD, making the average cost of pulling this card roughly $923 USD due to its 1-in-363 rarity.
Buy from Auction House
Because the Spectral Tiger Cub became cageable in Patch 5.0.4 (Build 16004), previously learned copies can be caged and sold, meaning you can purchase a caged version directly from the in-game Auction House without needing a physical card.
Note the Trading Post Version
The version of this pet obtained from the Trading Post cannot be caged or sold on the Auction House, but if you also own a TCG or Auction House copy, that separate copy remains fully cageable and tradeable.
Tips
Other spectral-themed pets include
Spectral Porcupette, and related spectral mounts include Reins of the Spectral Tiger and 
Reins of the Spectral Steed — see the video guide for more context on this pet.
