Onions wrote several collections of ghost stories, of which the best known is Widdershins (1911). It includes the novella The Beckoning Fair One, widely regarded as one of the best in the genre of horror fiction, especially psychological horror. On the surface, this is a conventional haunted house story: an unsuccessful writer moves into rooms in an otherwise empty house, in the hope that isolation will help his failing creativity. His sensitivity and imagination are enhanced by his seclusion, but his art, his only friend and his sanity are all destroyed in the process. The story can be read as narrating the gradual possession of the protagonist by a mysterious and possessive feminine spirit, or as a realistic description of a psychotic outbreak culminating in catatonia and murder, told from the sufferer's point of view. The precise description of the slow disintegration of the protagonist's mind is terrifying in either case.