Chained to the Rocks is a rare Enchantment — Aura card from Theros (THS), collector number 4. Current market price: $0.30 (foil $3.17), TCGplayer market prices via Scryfall.
Enchant Mountain you control When this Aura enters, exile target creature an opponent controls until this Aura leaves the battlefield. (That creature returns under its owner's control.)