This is the Mirage Caller 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: Battlecry: Choose a friendly minion. Summon a 1/1 copy of it.
You can get Mirage Caller by opening packs from the Journey to Un’Goro set.
*Another pick for the deathrattle quest decks.