Nils' Transformation
Nils used to capture animals just to get pleasure out of torturing them. He torments a mythological creature along with torturing other animals. The animals used to plead with him to free them, but Nils doesn't bother about their pain. It is ironical that Nils is transformed into an animal and he understands their pain only after his transformation. Prior to that, the cruel acts used to give him a kind of satisfaction. He didn't even spare his domestic animals. He grabs his cat by snatching its tail regardless of hurting it. He stops a goose from flying with its flock and enjoys torturing it. After transforming into an animal, he experiences the pain and promises to be kind towards others. Tomette asked him to mend his ways but he didn't act upon his advice. He refused the get reward by freeing the Tomette and preferred capturing him.
Animal Life
It is ironical that although Nils was a human being but he lacks the compassion, sympathy, kindness and caring nature which is usually associated with human beings. It is after living a life of an animal that he gets acquainted with these human traits. Nils learns the most important lessons of his life by spending the life of an animal among other animals. During his life as human, he was devoid of everything which he gained after embarking on a journey with a flock of geese. He got to know about various aspects of Sweden's culture and it's values.
Human Self
Another irony in the book is that Nils refuses to return to his human state after changing his ways as an animal. After coming across the cat, Osa and Mats, Nils realizes his faults and the sins which he committed by inflicting violence upon the animals. He mend his ways and swears to be sympathetic towards others. When he lives a week without torturing anyone and demonstrates a compassionate behavior, Tomette attempts to transform him into his real self but Nils refuses to become a human again. Eventually he comes back to his initial state but he is changed altogether and the people around him notice this change.
Nils Journey
Nils was a young boy who was hated by everyone around him because of his habits. He only loves sleeping and eating and his parents also complains about him. Their remarks about their only son were not good. His favourite past time was to annoy others and to hurt the animals. After his transformation into a Tomette, he didn't eat, sleep or hurt others. It is ironical that he could only talk to the animals during his journey. He would never understand the life of an animal or empathize with humans if he doesn't embark on a journey. His journey with animals was a blessing in disguise for him because it made him a best person whom his parents couldn't recognize after he came back in his human form.
