Powder Keg 
Artifact
At the beginning of your upkeep, you may put a fuse counter on this artifact.
, Sacrifice this artifact: Destroy each artifact and creature with mana value equal to the number of fuse counters on this artifact.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL