Aspect of Wolf is a rare Enchantment — Aura card from Intl. Collectors' Edition (CEI), collector number 185. Current market price: $5.84, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +X/+Y, where X is half the number of Forests you control, rounded down, and Y is half the number of Forests you control, rounded up.