Aspect of Wolf [Unlimited Edition] Construct Set: HeartGold & SoulSilver: Undaunted

Set: HeartGold & SoulSilver: Undaunted Type: Lightning Rarity: Common Retreat cost: Colorless

Set: Betrayers of Kamigawa Type: Instant — Arcane Rarity: Rare Cost: {X}{U}{U} You may exile a blue card with converted mana cost X from your hand rather than pay this spell's mana cost

if Clockwork Avian attacked or blocked this combat

Set: Amonkhet Invocations Type: Legendary Creature — God Rarity: Mythic Cost: {3}{U}{B} At the beginning of your upkeep

If that mana is spent on a creature spell

Aspect of Wolf [Unlimited Edition] Construct Set: HeartGold & SoulSilver: UndauntedSet: Unlimited Edition Type: Enchantment Aura Rarity: Rare Cost: {1}{G} Enchant creature Enchanted creature gets +X +Y, where X is half the number of Forests you control, rounded down, and Y is half the number of Forests you control, rounded up.