Barbarian Ring (ODY) from Odyssey, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: John Avon
• Card Text:
  T: Add R to your mana pool. Barbarian Ring deals 1 damage to you.
  Threshold — R, T, Sacrifice Barbarian Ring: Barbarian Ring deals 2 damage to target creature or player. (Play this ability only if seven or more cards are in your graveyard.)