Evoke is a keyword ability.
It is an ability that lets you play a creature for a different cost, and then sacrifice it. Creatures with evoke have either a come into play ability or a leaves play ability. This ability was a staple in the Lorwyn block.
- 502.74a Evoke represents two abilities: a static ability that functions in any zone from which the card can be played and a triggered ability that functions in play. “Evoke [cost]” means “You may play this card by paying [cost] rather than paying its mana cost” and “When this permanent comes into play, if its evoke cost was paid, its controller sacrifices it.” Paying a card’s evoke cost follows the rules for paying alternative costs in rules 409.1b and 409.1f–h.