This is the Cat Trick HS Hunter Card being released as part of the collection from One Night in Karazhan.
The card reads: Secret: After your opponent casts a spell, summon a 4/2 Panther with Stealth.
So a new Hunter secret, and a really good one too. 4/2 Panthers with stealth appearing means they can’t be immediately targeted. Your opponents are always going to cast spells too, so it’s going to get activated, and the value of this secret is really good.
This is one of the best secrets since the originals like Explosive Trap and Freezing Trap. Looking forward to this card being released.