Urza, Chief Artificer
Legendary Creature — Human Artificer, {3}{W}{U}{B}
Oracle Text
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."