Making lightning tree figures (aka Lichtenberg Figures) using the transformer out of a microwave oven that produces about 2000 volts run on 120 VAC. A solution of sodium bicarbonate is painted on the wood to increase its conductivity, and then the transformer is applied. The circuit creates an unpredictable, treelike burn pattern.
Wood Burning With 2000 Volts of Electricity
Video by BradRussellis