Yharon, Jungle Dragon

Flying, Haste, Double strike, Vigilance
Put X +1/+1 counters on Yharon, Jungle Dragon,
where X is the amount of mana spent to cast him.
Whenever Yharon, Jungle Dragon deals
combat damage to a player, you gain health equal
to the amount of damage dealt to your opponent.
When Yharon, Jungle Dragon dies, shuffle your graveyard back into your library.