Green Ward

A single white mana buys a creature broad protection from green: no green blockers can deal with it in combat, no green removal that targets or deals damage can touch it, no green Aura can stick to it. It is one of five mono-white wards from the game's first set (alongside Black Ward, Blue Ward, Red Ward, and White Ward), each renting protection from one color for the same cost. That extra clause about the Aura is a relic of how the early rules team handled protection interacting with Auras: White Ward, in granting protection from its own color, would make the Aura an illegal attachment and threaten to detach itself, so the line patches that case. On Green Ward the patch never has to fire (nothing here threatens to knock the Aura off), but the whole cycle carried the same defensive boilerplate regardless. What survives is the historical record of protection as a static property you could rent for a single mana, before the color pie learned to charge more for that kind of color-hosing lockout. The cycle was left in amber, never reprinted into Standard, and quietly superseded by protection-granting instants and the later keyword-counter designs that fold the same effect into bigger packages.