Allegorical, Surrealistic.
Surrealism is a story that has dreamlike qualities in which the narrative has absurd or unrealistic elements. In Metamorphosis, Gregor becomes a giant insect. This is rather absurd and unrealistic. An allegory is when a story has a hidden meaning. Is Metamorphosis just about a guy turned into a bug? No. It's also about the alienating nature of society. Throughout the story, Gregor has no real friends with people outside of his family. Once he becomes a bug, even that is gone.
