Community
Devoted Crop-Mate
Creature — Human Warrior
You may exert this creature as it attacks. When you do, return target creature card with mana value 2 or less from your graveyard to the battlefield. (An exerted creature won't untap during your next untap step.)
Rulings (9)
If an exerted creature is already untapped during your next untap step (most likely because it had vigilance or an effect untapped it), exert's effect preventing it from untapping expires without having done anything.
Apr 18, 2017
You can't exert a creature unless an effect allows you to do so. Similar effects that "tap and freeze" a creature (such as that of Decision Paralysis) don't exert that creature.
Apr 18, 2017
If the mana cost of a card in your graveyard includes X, X is considered to be 0.
Apr 18, 2017
Legality
Formats by platform