The Black Gate is a mythic Legendary Land — Gate card from The Hobbit Commander (HOC), collector number 47. Current market price: $12.42 (foil $13.53), TCGplayer market prices via Scryfall.
As The Black Gate enters, you may pay 3 life. If you don't, it enters tapped. {T}: Add {B}. {1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.