Liberator, Urza's Battlethopter [The Brothers' War]

Set: The Brothers' War Type: Legendary Artifact Creature — Thopter Rarity: Rare Cost: {3} FlashFlyingYou may cast colorless spells and artifact spells as though they had flash.Whenever you cast a spell, if the amount of mana spent to cast that spell is greater than Liberator, Urza's Battlethopter's power, put a +1/+1 counter on Liberator.