Emptiness Orb

Everlasting (Once this card is in play, no effect may
cause this card to leave the battlefield.)
Put a -1/-1 counter on a creature for each damage
dealt to it by any source. Whenever a creature
dies, exile it. It's controller loses life equal to that
creatures converted mana cost.
{6}: Emptiness Orb loses everlasting, then exile it.
Any player may play this ability.