Arcane Proxy (Promo Pack) [The Brothers' War Promos]

Prototype (You can cast this spell with different mana cost, color, and size. It keeps its abilities and types.) 1UU | 2/1

When Arcane Proxy enters the battlefield, if you cast it, exile target instant or sorcery card with mana value less than or equal to Arcane Proxy's power from your graveyard. Copy that card. You can cast the copy without paying its mana cost.