Goblin Boom Keg is a uncommon Artifact card from Fate Reforged (FRF), collector number 159. Current market price: $0.07 (foil $0.21), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, sacrifice this artifact. When this artifact is put into a graveyard from the battlefield, it deals 3 damage to any target.