Metamorphosis is a novella by Franz Kafka. It has been called one of the seminal works of fiction of the 20th century and is studied in colleges and universities across the Western world.
The story begins with a traveling salesman, Gregor Samsa, waking to find himself transformed (metamorphosed) into a large, monstrous insect-like creature. The cause of Gregor's transformation is never revealed, and Kafka himself never gave an explanation. The rest of Kafka's novella deals with Gregor's attempts to adjust to his new condition as he deals with being burdensome to his parents and sister, who are repelled by the horrible, verminous creature Gregor has become.
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 ungeheur Ungeziefer, literally "monstrous vermin"). He reflects on how dreary life as a traveling salesman is. As he looks at the wall clock, he notices that he has overslept and missed his train for work. He ponders the consequences of this delay. Gregor becomes annoyed at how his boss never accepts excuses or explanations from any of his employees no matter how hard-working they are, displaying an apparent lack of trusting abilities. Gregor's mother knocks on the door, and he answers her. She is concerned for Gregor because he is late for work, which is unorthodox for him. Gregor answers his mother and realizes that his voice has changed, but his answer is short, so his mother does not notice. His sister, Grete, to whom he is very close, then whispers through the door and begs him to open it. He tries to get out of bed but is incapable of moving his body. While trying to move, he finds that his office manager, the chief clerk, has shown up to check on him. He finally rocks his body to the floor and calls out that he will open the door shortly.
Offended by Gregor's delayed response in opening the door, the clerk warns him of the consequences of missing work. He adds that Gregor's recent performance has been unsatisfactory. Gregor disagrees and tells him that he will open the door shortly. Nobody on the other side of the door has understood a single word he had uttered as Gregor's voice has also transformed, and they conclude that he is seriously ill. Finally, Gregor manages to unlock and open the door with his mouth. He apologizes to the office manager for the delay. Horrified by Gregor's appearance, his mother faints, and the manager bolts out of the apartment. Gregor tries to catch up with him, but his father drives him back into the bedroom with a cane and a rolled newspaper. Gregor injures himself squeezing back through the doorway, and his father slams the door shut. Gregor, exhausted, falls asleep.