The Metamorphosis

The Metamorphosis (German: Die Verwandlung) is a novella written by Franz Kafka which was first published in 1915.

One day, Gregor Samsa, a traveling salesman, wakes up to find himself transformed into a giant insect (the most common translation of the German description ungeheuer Ungeziefer, literally "monstrous vermin"). He reflects on how dreary life as a traveling salesman is.

Souce: Wikipedia