Gwig was the sorcerer of the Mangaboos, the Vegetable Kingdom. He challenged the Wizard (formerly of Oz) to a magical contest, whereupon his final task was to deprive the Wizard of air via magical means.
The Wizard, out of exasperation, drew a sword from his pocket and sliced the sorcerer in half. The latter split like a turnip.
Afterwards, the Prince of the Mangaboos buried the sorcerer's remains in the garden so that a new sorcerer would grow from the ground.