Mantle of the Ancients is a rare Enchantment — Aura card from Fallout (PIP), collector number 165. Current market price: $4.48 (foil $8.78), TCGplayer market prices via Scryfall.
Enchant creature you control When this Aura enters, return any number of target Aura and/or Equipment cards from your graveyard to the battlefield attached to enchanted creature. Enchanted creature gets +1/+1 for each Aura and Equipment attached to it.