Joe, KD6-3.7

Haste, First Strike
Whenever Joe, KD6-3.7 attacks, discover X,
where X is the number of artifacts you control.
(Exile cards from the top of your library until you
exile a nonland card with mana value X or less.
Cast it without paying its mana cost or put it into
your hand. Put the rest on the bottom in a random
order.)