Champion of Sealed Souls

If a creature card would be put in your graveyard
from the battlefield, you may pay {w/b} and seal it instead. If you do, put a +1/+1 counter on
Champion of Sealed Souls.
{2}, Pay 2 life, Remove X +1/+1 counters from Champion of Sealed Souls: Unseal up to one
sealed creature card you own with mana value X
or less.