Willo the Wisp beech wood in Oxfordshire, near the director's home. Kenneth Williams provided voices for all of the characters. The principal narrator, Willo the Wisp, was a blue, floating creature drawn as a caricature of him, while the name refers to the ghostly light will-o'-the-wisp from folklore. The other main characters were Arthur the caterpillar (as a gruff cockney), Mavis Cruet, a plump, clumsy fairy with an erratic, magic wand, and the principal antagonist, Evil Edna, a witch in the form of a walking, talking television set who could zap people with her aerials. Other characters included Carwash, a snooty bespectacled cat
Will-o'-the-wisp and confounding. Will-o'-the-wisp appear in folk tales and traditional legends of numerous countries and cultures; notable will-o'-the-wisp include St. Louis Light in Saskatchewan, Marfa lights of Texas, the Naga fireballs on the Mekong in Thailand, and the Hessdalen light in Norway. While urban legends, folkore, and superstition typically attribute will-o'-the-wisps to ghosts, fairies, or elemental spirits, modern science often explains them as natural phenomena such as bioluminescence or chemiluminescence, caused by the oxidation of phosphine (PH), diphosphane (PH), and methane (CH) produced by organic decay. The term "will-o'-the-wisp" comes from "wisp", a bundle of sticks or paper sometimes used as