2020-08-07
If no card is imprinted on Chrome Mox, it can't add mana. It can never add {C}, even if the imprinted card has a colorless mana symbol in its mana cost.
2020-08-07
If you imprinted a multicolored card, you choose one of that card's colors each time you tap Chrome Mox for mana.
Printings
Secret Lair 30th Anniversary Countdown Kit
(mythic)