Maylith, Essence Conduit

{x}{w}{b}, Pay {x} life {t}: Maylith deals {x} damage
to target creature or player, herself, and her
controller. Then each opponent who was
not dealt damage this way gains {x} life.
Whenever you gain life, if an opponent has
lost life this turn you may pay up to {x} where {x} is the amount of life you gained,
if you do draw {x} cards.