Whenever The Mightstone and Weakstone enters the battlefeild, choose one —

•Draw two cards.

•Target creature gets -5/-5 until end of turn.

{T}: add {C}{C}. This mana can't be spent to cast nonartifact spells

(Melds with Urza, Lord Protecter.)

+2: Artifact, instant, and sorcery spells you cast this turn cost {2} less to cast. You gain 2 life

+1: Draw two cards, then discard a card

-3: Exile target nonland permanent

-10: Artifacts and planeswalkers you control gain indestructible until end of turn. Destroy all nonland permanents