The supernatural in Something Wicked This Way Comes is used primarily in connection with perpetrating evil, although "good" magic is ultimately used to conquer the carnival freaks. Supernatural elements within the novel are powered by human emotion and belief, however. Evil has no hold over characters if they make conscious choices in opposition to it, and the good magic ultimately used to conquer evil is grounded in positive human emotions such as love. Additionally, we see that Bradbury's is a particular brand of supernatural, one intimately connected to the imaginative outlook of adolescent boys.
The supernatural in Something Wicked This Way Comes stems from real life issues like love, community, and temptation.
The supernatural element of this novel is simply the dark version of the supernatural element in Bradbury's novel Dandelion Wine.