"Being struck by lightning is a dangerous and scary experience and can even be fatal. Sometimes, the electrical discharge can leave a tattoo-like marking or scar known as a Lichtenberg figure. The patterns created are known to be examples of fractals."

http://en.wikipedia.org/wiki/Lichtenberg_figure
http://twistedsifter.com/2012/03/lichtenberg-figures-lightning-strike-scars/