Klauth, Unrivaled Ancient (Foil) (AFC) from Forgotten Realms Commander, available at 401 Games Canada.

• Rarity: Mythic Rare
• Finish: Foil
• Artist: Andrew Mar
• Card Text:
  Flying, haste
  Whenever Klauth, Unrivaled Ancient attacks, add X mana in any combination of colors, where X is the total power of attacking creatures. Spend this mana only to cast spells. Until end of turn, you don't lose this mana as steps and phases end.