Whilst under the influence of a powerful plant-based hallucinogenic, one man had a vision of Vulthoom as looking like an enormous alien plant, although this may not be its actual form, and until the being awakens from its long slumber and ventures forth, no one may know it’s true appearance.
Although believed by the Martian Aihai to be their own version of Satan, Vulthoom is in reality a highly intelligent and technologically advanced alien. Exiled from its own reality by others of its kind for reasons unknown, Vulthoom assumed control of Mars in ages long past, but has since slipped into a millennia-long torpor and now rests in the subterranean city of Ravormos. There it sleeps, dreaming of the day when it will awaken and bring to heel its next conquest, the planet Earth.
- Vulthoom (1935), by Clark Ashton Smith.