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 may also produce electricity, channeled up to the surface through the soil via a column of vaporized water, there somehow appearing as earth lights. This would explain why the lights appear electrical, erratic, or even intelligent in their behavior. The will-o'-the-wisp phenomena may occur due to the bioluminescence of various forest dwelling micro-organisms and insects. The eerie glow emitted from certain fungal species, such as the honey fungus, during chemical reactions to form white rot could be mistaken for the mysterious will-o'-the-wisp or foxfire lights. There are many other bioluminescent organisms that could create the illusions of fairy lights, such