The pet might introduce Harry to new magical creatures or areas. For instance, if it's a cat that loves to explore the Forbidden Forest, it could lead Harry to discover hidden places or meet other magical beings that he wouldn't have encountered otherwise. This could expand his knowledge of the wizarding world and his own powers.
It could be a snowy owl, just like Hedwig. In the original series, Hedwig was Harry's loyal and beautiful owl. A fanfiction might follow this idea and have Harry find a young snowy owl that he bonds with immediately.
In the world of fanfiction, the cat could have some special powers. These powers could lead Harry into new adventures and help him develop new skills. For instance, if the cat can sense dark magic, it could alert Harry to approaching danger. This would change Harry's life as he becomes more vigilant and learns how to use the cat's power to protect himself and others at Hogwarts.
The pet bat could make Harry's life more interesting. It could be his companion during lonely times, like when he's in his dormitory and the others are asleep.
The dog could provide Harry with unconditional love and companionship. In the often - lonely world of Hogwarts where he has so many secrets and enemies, the dog would be a constant friend. It could also help him relax, like when he's stressed about exams or Voldemort.
It might change Harry's perspective on magic. If the cat has some unique magical powers, Harry could learn a lot from it. For example, if the cat can transform into different animals, Harry might be inspired to study more about transfiguration magic. Also, taking care of the cat could teach Harry more about responsibility.
His life changes significantly. Firstly, he no longer has to hide the abuse. He can be more open about his feelings and experiences. This could lead to him getting the help he needs, like emotional support from his friends.
Well, in some fanfictions, he might find it in the Forbidden Forest during one of his adventures. Maybe it was injured and he felt a connection to it, so he decided to take it as a pet.
The relationships that Harry was supposed to form later in life, like his friendships with Ron and Hermione, would never happen. And the whole wizarding world would be different. Without Harry, there might not be someone to stand up to Voldemort in the same way. So, the power balance in the wizarding world would be completely shifted. Also, the mystery around Harry's scar and his connection to Voldemort would be left unresolved in a way that leaves the story with a sense of incompleteness.
The snake could help Harry find his way around Hogwarts. You know, Hogwarts is a huge and complex place. The snake might be able to sense the different magical auras of different areas and lead Harry to where he needs to go, like the library when he has to study for an important exam or the Room of Requirement when he's in a tight spot.
Let's say his pet is a dementor. It would change the whole atmosphere of the story. The characters would constantly be in fear of having their souls sucked out. It could also be used to guard important places. For instance, Voldemort might place it near the entrance of his lair. This would make it extremely difficult for the heroes to approach as they have to deal with this terrifying creature first. Also, it could spread a sense of despair among the wizarding community, making people more vulnerable to Voldemort's control.