The Dauntless, Diana's Hunger

Flying
When The Dauntless, Diana's Hunger enters the battlefield or attacks, you may destroy target artifact, enchantment, or land. If you do, create a colourless artifact token named Gold. It has "Sacrifice this artifact: Add one mana of any color to your mana pool."
"Many don't know the riches of Clew Bay were seldom first discovered by moi." -Cpt. Diana