Valigar, the Swamp-Stalker

Death-touch
Whenever a permanent leaves the battlefield put a +1/+1 on Valigar, the
Swamp-Stalker
Whenever Valigar, the Swamp-Stalker deals combat damage, destroy any number of non land permanents with combined mana cost less than the number of counters on Valigar,
the Swamp-Stalker.