Puff, the Magic Dragon

Flying, trample, hexproof
Puff the Magic Dragon is every color.
Whenever an opponent casts a spell, Puff the Magic Dragon deals 10 damage to any target.
{5}: Put X +1/+1 counters on each Dragon you control, where X is Puffs power. You gain 10 life.
Prevent all damage that would be dealt to Puff this turn. You gain that much life.