Skithiryx, Withered Soul

Wither, Flying
{b/g}{b/g}{b/g}, Pay X life: Put the bottom X cards of your deck into your graveyard, then you may cast a card with converted mana cost X or less from your graveyard or exile without paying its mana cost. You may only activate this ability once per turn.
{g}{b}: Regenerate Skithiryx