In Stephen King’s Desperation, the ancient evil entity is Tak.
Tak is a supernatural being imprisoned beneath the fictional Nevada mining town of Desperation. The entity can possess human hosts, but those bodies deteriorate quickly, forcing Tak to move from one person to another. Its influence also extends to animals, including coyotes, buzzards, spiders, and scorpions.
The novel begins when travelers on desolate Highway 50 are arrested by Collie Entragian, a police deputy controlled by Tak. The captives gradually discover that the town’s mass violence is not simply the work of a human killer. Tak has been released from an old mine shaft and is using people and wildlife to spread terror.
Tak is sometimes confused with other Stephen King villains, especially Pennywise, the Crimson King, or Randall Flagg. Those figures belong to different stories and do not serve as the central entity in Desperation. Published in 1996, the novel appeared alongside The Regulators, a “mirror” novel published under King’s Richard Bachman name. In both books, many character names recur, but their identities and circumstances differ.