Last Light of Durin's Day is a rare Enchantment card from The Hobbit (HOB), collector number 228. Current market price: $0.40 (foil $0.78), TCGplayer market prices via Scryfall.
Whenever a Mountain you control enters, put a quest counter on this enchantment. If it has six or more quest counters on it, sacrifice it. If you do, search your hand and/or library for a Dragon card and put it onto the battlefield. If you search your library this way, shuffle. Mountaincycling {2} ({2}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)