Stormbreath Dragon
Theros — mythic
Creature — Dragon
Stormbreath Dragon rulings:
2013-09-15: For each opponent, count the number of cards in that player's hand when the last ability resolves to determine how much damage Stormbreath Dragon does to them.
2013-09-15: Once a creature becomes monstrous, it can't become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.
2013-09-15: Monstrous isn't an ability that a creature has. It's just something true about that creature. If the creature stops being a creature or loses its abilities, it will continue to be monstrous.
2013-09-15: An ability that triggers when a creature becomes monstrous won't trigger if that creature isn't on the battlefield when its monstrosity ability resolves.