Urza's Incubator [Commander 2015]

Set: Commander 2015 Type: Artifact Rarity: Rare Cost: {3} As Urza's Incubator enters the battlefield, choose a creature type. Creature spells of the chosen type cost {2} less to cast. "Stop thinking like an artificer, Urza, and start thinking like a father!"—Rayne, chancellor of the Tolarian Academy