Bilbo, Of The Shire

Every time Bilbo, Of The Shire kills a creature,
put a +1 +1 counter on them.
Once Bilbo, Of The Shire's power and toughness
are both 5, this ability does not activate anymore.
"It's a dangerous business, going out your front door.
You step onto the road,
and if you don't keep your feet, there's no knowing
where you might be swept off to"
- Bilbo Baggins