This is the Crystalline Oracle HS Priest Card from the Journey to Un’Goro expansion due for release in April.
It’s a Priest class minion and the card reads: Deathrattle: Copy a card from your opponent’s deck and add it to your hand.
You can get Crystalline Oracle by opening packs from the Journey to Un’Goro set.
*This card synergizes with both Elemental cards and the Awaken the Makers quest card.