Chrome Mox

Set
Eternal Masters
Rarity
Mythic
Text
Imprint — When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand. T: Add one mana of any of the exiled card's colors.
Legality
Legal in: Commander, Legacy, Vintage
Banned in: Duel, Modern
Rulings
2016-06-08: If no card is imprinted on Chrome Mox, it can’t add mana to your mana pool. It can never add colorless mana to your mana pool, even if the imprinted card has a colorless mana symbol in its mana cost.

2016-06-08: If you imprinted a multicolored card, you choose one of that card’s colors each time Chrome Mox’s ability resolves.