Nicol Bolas, Darkness

: If a creature or planeswalker your opponent/s controls would be put into a graveyard, exile it instead. This spell can't be countered.
+2: Put a -1/-1 counter on each creature your opponent/s control. You gain 3 life.
-12: Each opponent loses X life, discards X cards,sacrifices X creatures and you gain X life, while X is the number of creatures you control plus 6.