I wonder how DIY this is? What kind of plastic do they use and does it have to be prepped up somehow?

I guess you need extremely high voltage, which you can easily recreate at home.

Hmmhhmmh. Well, if the only way to do this is the one mentioned in wikipedia, I think I won't be doing it anytime soon. At least in my home that is

"Modern Lichtenberg Figures can also be created within solid insulating materials, such as acrylic (polymethyl methacrylate or PMMA) or glass by injecting them with a beam of high speed electrons from a linear electron beam accelerator (or Linac, a type of particle accelerator). Inside the Linac, electrons are focused and accelerated to form a beam of high speed particles. Electrons emerging from the accelerator have energies up to 25MeV and are moving an appreciable fraction (95 - 99+ percent) of the speed of light (relativistic velocities). If the electron beam is aimed towards an acrylic specimen, the electrons easily penetrate the surface of the acrylic, rapidly slowing down as they collide with molecules inside the plastic, finally coming to rest deep inside the specimen. Since acrylic is an excellent electrical insulator, these electrons become temporarily trapped within the specimen, forming a plane of excess negative charge. Under continued irradiation, the amount of trapped charge builds, until the effective voltage inside the specimen reaches millions of volts. Once the electrical stress exceeds the dielectric strength of the plastic, some portions suddenly become conductive in a process called dielectric breakdown."

hmm actually, I wonder if TV would work for this one. Nah, I have a feeling it needs something a bit more on the industrial level.

damn, silly me, was just looking through my comment and forgot to put a 't there:
"I guess you need extremely high voltage, which you can't easily recreate at home."