Beastmaster Ascension is a rare Enchantment card from Commander 2015 (C15), collector number 176. Current market price: $5.58, 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.