Stormbreath Dragon

Oracle Text

Flying, haste, protection from white

5RR: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

When Stormbreath Dragon becomes monstrous, it deals damage to each opponent equal to the number of cards in that player's hand.

Card Rulings

9/15/2013 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.
9/15/2013 Once a creature becomes monstrous, it can’t become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.
9/15/2013 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.
9/15/2013 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.