Urza, Lord Protector // Urza, Planeswalker

Legendary Creature — Human Artificer

Artifact, instant, and sorcery spells you cast cost less to cast. : If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery.