Kamdell, Throne Usurper

Other creatures have Dethrone.
Whenever one or more creatures with a +1/+1 counters deals combat damage to a player other
then you, its controller reveals that many cards
from the top of there library. They may cast a
card with converted mana cost equal to the
number of creatures that attacked this turn until
the next end step. Put the other revealed cards
on the bottom of their owners library in a
random order.