Kabuto Yakushi, Serpent Sage

{u/b}{x}, {t}: Exile X target creature cards from your graveyard.
Whenever a creature you control deals combat
damage to a player, you may exile a target
creature card from that player's graveyard.
You may cast creature spells exiled by Kabuto
Yakushi, Serpent Sage. You may spend mana
as though it were mana of any color to cast
these spells.