Osmium Destruction

Firststrike, Trample.
When Osmium Destruction deals combat damage
put that many rune counters on it.
Remove any number greater than 0 rune
counters from Osmium Destruction: Destroy
target nonland permanent with mana value equal
or less than to the number of counters removed.
Osmium Destruction gets +1/+1 for every rune counter on it.
Crew 5