Urza, Powerstone Prodigy
From The Brothers' War set
Urza, Powerstone Prodigy
Legendary Creature — Human Artificer
1/3
Vigilance
, : Draw a card, then discard a card.
Whenever you discard one or more artifact cards, create a tapped Powerstone token. This ability triggers only once each turn. (The token is an artifact with " : Add . This mana can't be spent to cast a nonartifact spell.")