There is never an explanation given as to why this transformation or metamorphosis has occurred. One explanation for this may be the many qualities that Gregor 's character shares with bugs and how they are perceived by humans.
He is a typical hardworking man trying to pay off debts. Kennedyand still critics stumble over that single opening line. At last, Gregor himself manages to open the door, and everybody could see the creature he had become. Monsters may look frightening, have unnatural body proportions, or even a dark and evil aura.
A metamorphosis is also the mental, social, and physical change that a person goes through. Prior to his death he had no intentions of publishing any work until in when his friend Max Brod convinced him to.
In particular, it questions the abandonment and their ability to turn back to someone who has sacrificed most of his life trying to provide in the family that in the end chose to neglect and accept his change as a bug.