Urza, Chief Artificer is a mythic Legendary Creature — Human Artificer card from Magic Online Promos (PRM), collector number 105800.
Affinity for artifact creatures (This spell costs {1} less to cast for each artifact creature you control.) Artifact creatures you control have menace. At the beginning of your end step, create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."