Spreading Plague

When casting Spreading Plague, create X copies of
this spell, exiled and with suspend X.
Until end of turn, whenever a creature dies this
turn its owner loses X life.
Choose X different creatures. Put X -1/-1 counters
on each of them. Until end of turn, whenever a
creatures toughness is reduced to 0 or below by
-1/-1 counters, that creatures owner must put two
-1/-1 counters on a single creature or one -1/-1
counter on each of two different creatures.