Ezial, Dominate Scout.

Covertness.
Relieve 4. (You may pay 4 to swap this creature
with a creature in your hand with less health
than it. Use this ability only on your turn.)
Whenever you relieve a creature in play, you
may reveal Ezial from your hand. If you do, you
may search your deck for a copy of the card
being put in play.