Death's Present

destroy X creatures, destroy X artifacts, destroy X
enchantments, all your creatures, and artifacts get
+X/+X until Death"s Present dies, and opponent
loses X life, where X is how much you payed
to cast this spell. Sacrifice this creature: you gain
5 life and opponent loses 2 life for each creature
with a +1/+1 counter on it
pay X and sacrifice this creature: you gain 6 life.