This is the New Card Book Wyrm coming with the release of the Hearthstone adventure One Night in Karazhan on the 11th August.
It’s a neutral card with the text: Battlecry: If you’re holding a Dragon, destroy an enemy minion with 3 Attack or less.
This will almost certainly find its way into some dragon decks, I’m not sure about Dragon Warrior as it’s not an aggressive-tempo card. It will be more use in control decks like Dragon Priest and builds like this.
Interesting card though, and good to see more dragon synergy to play around with.