There's a joke in here somewhere about metal and electricity, but that wouldn't really be conducive to the point. It's a tesla coil that plays metal.
So what you're going to want to do is click play above watch a tesla coil play some Black Sabbath at the Centre of Life in Newcastle. The jams are followed up by some really interesting science explanation that I can't properly summarize because science. It's a really interesting read that's included with the video as well, so just in case you've got your chub on today, this'll fulfill that. Let's review; science, electricity, and metal. Did I need to say anything else?