Powder Keg | Magic: The Gathering
Formats Powder Keg is Legal in
Official Oracle Text for Powder Keg
, Sacrifice Powder Keg: Destroy each artifact and creature with converted mana cost equal to the number of fuse counters on Powder Keg.
Official Rulings for Powder Keg
10/4/2004 : Putting on a counter is optional. If you forget, you can't go back later even if it is something you usually do.