Garrik, the Eternal Flame

Unkillable (This creature cannot leave the battlefield by any means.)
Learn over time — Whenever one or more creatures enters the battlefield, Garrik, the Eternal Flame gets that many +1/+1 counters.
Uncollapsible Mind — If Garrik, the Eternal
Flame were to gain an ability, put a counter on Garrik, the Eternal Flame of that ability.