Franz Kafka had quite a wild imagination. And a lot of distrust of early twentieth-century society. How else could someone dream up a story about a guy who wakes up one morning to find himself turned into a huge cockroach? (At least, we think it's a cockroach. Kafka doesn't totally specify. Anyway it's some sort of icky bug.)
Metamorphosis is considered one of the most important works of twentieth-century literature. And rightly so. Why? Well, the Formalists would say because it's got so much defamiliarization going on. It's a story that messes with your head. And your perception. And that starts right from the very beginning.