Beastmaster Ascension is a rare Enchantment card from Commander 2016 (C16), collector number 142. Current market price: $6.59, TCGplayer market prices via Scryfall.
Whenever a creature you control attacks, you may put a quest counter on this enchantment. As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.