The Metamorphosis is approximately half fantastic and half realistic. The combination places it within surrealism more than within horror. The fundamental premise is not possible: Gregor is the character most easily identified as fantastic. Because the entire story hinges on his transformation, many interpretations see the entire story as his dream. In this view, the unreal aspects are contextualized within an imagined scenario—that is, Gregor did not wake up that morning but experiences all the events in his dream.

In either interpretation, the action is frightening because much of it is realistic. Gregor hates his job. He feels relieved at the change that prevents him from doing his job. He feels deeply obligated to his family, who do not appreciate him. In fact, his father has been lying to him about their finances. All these features characterize many people's lives.

Other aspects are not physically impossible but are implausible. People are capable of such actions, but their use in the particular situation is unlikely. One such feature is Gregor's father throwing apples that get stuck in his back. It shows his hypocrisy in supposedly trying to feed his son but instead physically assaulting him. The episode creates a strong visual image, but the scene is not realistic.