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"Big Book Building"
Land
: Add . , Pay 1 life: Add one mana of any color. Spend this mana only to cast an instant or sorcery spell. : If this land isn't a creature, it becomes a 2/4 Wizard creature with "Whenever you cast an instant or sorcery spell, this creature gets +1/+0 until end of turn." It's still a land.
rare · #257 · sos
Previewed: March 31 · Spoiled by Wizards of the Coast