Ray Bradbury first wrote 'Something Wicked This Way Comes' as a screenplay in 1952, after watching Gene Kelly in Singin' in the Rain (1952), which Bradbury thought was the greatest musical ever made. Bradbury showed Kelly the screenplay, and Kelly was so impressed that he wanted to make it his next picture. When Kelly shopped the story around to potential backers in 1958, he was unable to raise any money for the project. It was only after this failure that Bradbury rewrote the story as a novel, which incorporated some elements from his 1948 story "Black Ferris," and was published in 1962. Bradbury dedicated the novel to Kelly.
After a poorly received test screening, Disney held back the release of the movie for a year to re-edit, film additional and replacement scenes (including special effects sequences) with a second unit director, add opening narration, and hire James Horner to rewrite a completely new score, all of which added millions to the budget. When watching the film, it's quite obvious which scenes, such as the spider attack and the mirror maze climax, were filmed nearly a year after the original production had wrapped. Reportedly, Ray Bradbury and the original filmmakers were not pleased with the studio's intervention, nor the effects added. The picture ended up being a flop when it was finally released in 1983, despite Disney's attempts to make it more audience-friendly.
A special-effects sequence that took place at the beginning of the film was cut shortly before the movie hit theaters. In this sequence, the carnival materializes from the smoke of the train, the smoke from the engine "becomes ropes and canvas tents. Tree limbs grow together to form a Ferris wheel and a spider web mutates into a wheel of fortune." This sequence was the first time that computer animation was used to animate organic material, and it was combined with traditional animation. The scene was deemed not convincing enough by Disney executives and was cut from the film at the very last minute. The deleted scene was described in the issue of "Twilight Zone Magazine" released the same month as the film, which assumed the scene was going to be in the final print.
Disney made many changes to the film which writer Ray Bradbury and director Jack Clayton did not intend. Many extra special effects scenes were shot by a second unit director after original production wrapped, and other changes were made before its release. According to the laserdisc commentary by Bradbury, much of his original intentions for the movie were destroyed.