Serra Avatar [Urza's Saga] Oathbreaker Whenever an opponent taps a

Whenever an opponent taps a land for mana

Set: Amonkhet Invocations Type: Instant Rarity: Mythic Cost: {1}{U}{U} Buyback {3} (You may pay an additional {3} as you cast this spell

As long as you have 30 or more life

Set: Seventh Edition Type: Artifact Rarity: Rare Cost: {1} Creatures with power 3 or greater don't untap during their controllers' untap steps

They tunneled

Serra Avatar [Urza's Saga] Oathbreaker Whenever an opponent taps aSet: Urza's Saga Type: Creature Avatar Rarity: Rare Cost: {4}{W}{W}{W} Serra Avatar's power and toughness are each equal to your life total. When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.