Goblin Boom Keg 
Artifact
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.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL