Necromaster Dragon

Flying
Whenever this creature deals combat damage to a player, you may pay {2}. If you do, create a 2/2 black Zombie creature token and each opponent mills two cards.

Magic Online Promos

Dragons of Tarkir

Flying
Whenever Necromaster Dragon deals combat damage to a player, you may pay {2}. If you do, put a 2/2 black Zombie creature token onto the battlefield and each opponent puts the top two cards of his or her library into his or her graveyard.

Dragons of Tarkir Promos

Necromaster Dragon’s last ability will trigger once for each player it deals combat damage to. For each of these abilities, you may pay {2} only once.