Dragons of Tarkir — Uncommon
Creature Bird Warrior
Aven Sunstriker rulings:
2/25/2015 : Turning a face-down creature with megamorph face up and putting a +1/+1 counter on it is a special action. It doesnt use the stack and cant be responded to.
2/25/2015 : If a face-down creature with megamorph is turned face up some other way (for example, if you manifest a card with megamorph and then pay its mana cost to turn it face up), you wont put a +1/+1 counter on it.
2/25/2015 : Megamorph is a variant of the morph ability. You can find more information on morph on cards with morph from the Khans of Tarkir set.