The Glowing Pickle
A pickle is placed into a light socket and a tungsten electrode is put through the top. The lights are turned low and current is sent arcing through the pickle from a variac that had been plugged into a wall outlet. The pickle glows brightly for a few seconds and eventually starts to smoke.
The pickling process involves soaking a cucumber in a concentrated salt solution (or brine). Water flows out of the cucumber and salt flows into the cucumber, creating a salty, dehydrated cucumber (or pickle). The inside of the pickle is essentially an electrolyte solution, and conducts electricity.