Celestial Kirin

Legendary Creature - Kirin Spirit 3/3, 2WW (4)
Flying

Whenever you cast a Spirit or Arcane spell, destroy all permanents with that spell's converted mana cost.¹
All bow at its visitation-some in awe, some in honor, some in fear.
Illus. Adam Rex

Gatherer Card Rulings [Nov 2009]

• 6/1/2005: If the Spirit or Arcane spell has {X} in the mana cost, then you use the value of {X} on the stack.  For example, Shining Shoal costs {X}{W}{W}. If you choose X = 2, then Shining Shoal's converted mana cost is 4. Shining Shoal also has an ability that says "You may exile a white card with converted mana cost X from your hand rather than pay Shining Shoal's mana cost"; if you choose to pay the alternative cost and exile a card with converted mana cost 2, then X is 2 while Shining Shoal is on the stack and its converted mana cost is 4.

Format Legality	Legal in Vintage, Legacy, Extended, MTGO Classic Banned in Standard
Printings (1/11)	Saviors of Kamigawa (Rare)