Aia'Thuma Soul Leviathan

({p/b} can be paid with either {b} or 2 life.)
Indestructible, Swamp-walk
Aia'Thuma has +1/+1 for every soul counter.
{ut}: Plague (Make all land swamps until end of turn.)
Soul Trader (Whenever a creature dies souls are gained if this card is in the game; spend soul counters to lessen the cost of this card and cast it from your hand, graveyard, or exile.)