anything else that takes batteries. As a few of you remember from the cookout I had a spare battery with me for my saber. After I got home I was sitting there and all of the sudden it felt like my leg was on fire in my pocket. I reached in and almost burned my hand on the battery that was in my pocket. I pulled it out and threw it across the room. I wasnt on fire but man was that thing hot. the only thing I can think of is I had my knife in the same pocket and the contacts on the battery were touching the knife for a long time. So a word to the wise....keep your batteries wrapped.