Mount Doom is a mythic Legendary Land card from The Hobbit Commander (HOC), collector number 50. Current market price: $8.62 (foil $12.17), TCGplayer market prices via Scryfall.
{T}, Pay 1 life: Add {B} or {R}. {1}{B}{R}, {T}: Mount Doom deals 1 damage to each opponent. {5}{B}{R}, {T}, Sacrifice Mount Doom and a legendary artifact: Choose up to two creatures, then destroy the rest. Activate only as a sorcery.