Xenos, Disruptive Seeker

Flying
Reveal Truth—At the beginning of your post -
combat main phase, if Xenos, Disruptive Seeker
dealt combat damage to an opponent this turn, that
player reveals X cards, at random, from his or her
hand, where X equals the number of spells you
cast this turn. You may cast a card from your hand,
with mana value less than, or equal to, the total
mana value of all cards revealed this way, this turn, without paying it's mana cost.