Command Tower [The Lost Caverns of Ixalan Commander] Phyrexian Elder Dinosaur whenever either of those creatures

whenever either of those creatures deals combat damage

{T}: Return target artifact or enchantment card from your graveyard to your hand

Set: Modern Masters 2015 Type: Instant Rarity: Common Cost: {1}{R} Destroy target artifact

Set: Dominaria United Commander Type: Land Rarity: Rare {T}: Add one mana of any color that a land an opponent controls could produce

Command Tower [The Lost Caverns of Ixalan Commander] Phyrexian Elder Dinosaur whenever either of those creaturesSet: The Lost Caverns of Ixalan Commander Type: Land Rarity: Common T: Add one mana of any color in your commander's color identity. Approach my tower on bended knee or depart from it as ash upon the wind. Gadwick, the Wizened