The Hound of the Night Sky

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