Artillery Enthusiast

Modified creatures you control have menace.
When Artillery Enthusiast enters the battlefield,
you may discard a card.
If you do, seek at card with mana value equal
to that card's mana value.
(To seek, exile the top card of your library until you
exile a card that meets the criteria. Put that card into
your hand. Then put all remaining cards exiled this
way on the bottom of your library in a random order.)