When Tezzeret's Gatebreaker enters the battlefield, look at the top five cards of your library. You may reveal a blue or artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
, , Sacrifice Tezzeret's Gatebreaker: Creatures you control can't be blocked this turn.
Because the last ability of Tezzeretâ€™s Gatebreaker doesnâ€™t change the characteristics of any permanents, the set of creatures affected by it is constantly updated. Creatures that come under your control later in the turn canâ€™t be blocked.