This is the Spiritsinger Umbra HS Card from the Journey to Un’Goro expansion due for release in April.
It’s a Neutral minion and the card reads: After you summon a minion, trigger its Deathrattle effect.
You can get Spiritsinger Umbra by opening packs from the Journey to Un’Goro set.
*Situational, but I can see this card finding a home in deathrattle/N’Zoth decks.