702.71 - Evoke
702.71a - Evoke represents two abilities: a static ability that functions in any zone from which the card can be cast and a triggered ability that functions on the battlefield. "Evoke <-cost->" means "You may cast this card by paying <-cost-> rather than paying its mana cost" and "When this permanent enters the battlefield, if its evoke cost was paid, its controller sacrifices it." Paying a card's evoke cost follows the rules for paying alternative costs in Rule 601.2b and Rule 601.2e through Rule 601.2g. [CompRules 2009/07/08]