Lichtenberg Figures
Here are two videos about creating Lichtenberg figures in wood, as well as a series of pictures.
Video: Lichtenberg Wood Burning (1:06)
Video: Make Lichtenberg Wood Art Safely (21:14)
It is possible to create beautiful patterns by shocking acrylic, a transparent plastic, with very high voltages.
Video: Huge 2.5 Million Volt Captured Lightning Sculpture Being Discharged (1:09)
Video: Electron-Filled Acrylic Cylinder (0:16)
Video: 3D Lichtenberg Figure in Acrylic (0:41)
Lichtenberg Figure - Downed Power Line
Lastly, when humans are struck by lightning, it can create result in Lichtenberg figure scars. Warning: Although these people survived being struck by lightning, the scarring is very extensive.
Lichtenberg Figure Lighting Scars on Neck
Lichtenberg Figure Lightning Scars on Arm