Gmork

Whenever a permanent an opponent controls is
put into a graveyard from the battlefield, put a
+1/+1 counter on Gmork.
At the beginning of your upkeep, if Gmork
has one or more +1/+1 counters on it, you may
remove all of them. If you do, exile each other
nonland permanent with mana value less than
or equal to the number of counters removed
this way.