The "Metamorphosis"

Gregor Samsa wakes up one day to find that he has for no apparent reason been turned into a giant bug. Not just a giant bug but rather a cockroach or a dung beetle. Although Gregor's physical appearance has completely undergone a change from the very beginning, as the story goes on more things gradually go through a "metamorphosis".
For example, at first Samsa isn't quite sure how to use his many new insect legs but as time goes on and Gregor is able to master his body as a bug he begins to crawl around just like any insect would. Not only this, but Gregor's human voice is there in the morning when he is able to yell out to his family from his room, however later on when the Chief Clerk arrives Gregor can no longer communicate with his human voice and instead, as the Chief Clerk refers to as an "animal voice" is sounded. Gregor's food preferences also start to make a change from wanting tasty human-like foods to preferring rotten cheese that his sister brings to him.
Besides the obvious changes that take place for Gregor becoming an insect there are other less obvious things such as Gregor finding comfort in being alone and in dark places to easily being startled much like any other insect would.
Even though Gregor physically looks like a giant bug, crawls around like a giant bug, makes giant bug noises, whatever a giant bug noise might be and prefers to munch on rotten cheese and garbage, is Gregor really completely a giant bug if he still feels human like emotions such as guilt, sadness, neglect or loneliness and these being only a few of the emotions that Gregor feels throughout the story.