Barbarian Ring is a uncommon Land card from Modern Horizons 3 (MH3), collector number 299. Current market price: $0.29 (foil $0.35), TCGplayer market prices via Scryfall.
{T}: Add {R}. This land deals 1 damage to you. Threshold — {R}, {T}, Sacrifice this land: It deals 2 damage to any target. Activate only if there are seven or more cards in your graveyard.