A plot could be that Snape's pet is a phoenix, which is a very rare and powerful magical creature. Harry Potter is intrigued by this phoenix and tries to get closer to it. Snape is initially against this but as the story progresses, he sees that Harry has a pure heart and allows him to interact with the phoenix. This could lead to a bond forming between Harry and Snape through their shared interest in the phoenix.
Imagine a fanfiction where Harry Potter's new pet, a small Pygmy Puff, gets lost in the dungeons. Snape, who is in charge of the dungeons, finds the Pygmy Puff first. Instead of being mean, Snape takes care of the Pygmy Puff. When Harry comes looking for it, he is surprised to see Snape's gentle side. This situation could start a series of events where they start to understand each other better.
In a fanfiction, there could be a story where a mysterious pet starts to appear around Hogwarts. It seems to have a connection to both Harry Potter and Snape. As they both investigate the origin of this pet, they discover that it is a key to an ancient magic that was once lost. They have to put aside their differences and work together to unlock the secrets of this magic, with the pet as their guide.
One plot idea could be that Harry, as a pet in this fanfiction universe, has some unique magical abilities that only Snape can understand and help him develop. For example, Harry might be able to communicate with magical creatures in a special way. Another idea is that Snape takes Harry under his wing as a pet to protect him from the real threats in the wizarding world that others don't see. Maybe there's a prophecy related to Harry's 'pet' status that Snape is trying to figure out.
Perhaps in the fanfiction, Snape and Harry are forced to team up to defend Hogwarts against a new, unknown dark force. They have to rely on each other's skills and knowledge, with Snape using his potions expertise and Harry his courage and Gryffindor - like bravado. Along the way, Snape shares some of his own experiences with dark magic and how to combat it, making Harry a more well - rounded wizard.
One interesting plot idea could be that Snape, in raising Harry, teaches him advanced potions from a very young age. Harry becomes a prodigy in potions, much to the surprise of the other Hogwarts students. Another idea is that Snape's strict but fair upbringing makes Harry more reserved and less impulsive, which changes the way he interacts with his friends. He might be more cautious and calculating in his actions, especially when dealing with enemies like Voldemort.
One plot idea could be that Dudley somehow gets involved in the wizarding world due to a magical accident. Snape, initially reluctant, has to keep an eye on him. Meanwhile, Harry is caught in the middle, trying to balance his relationship with Dudley and dealing with Snape's grumpiness. For example, Dudley could accidentally drink a potion meant for someone else and start showing magical abilities, leading to chaos and an unlikely alliance between him and Snape to reverse the effects.
One idea could be that Harry discovers the truth about his parentage early on. This changes his relationship with Dumbledore as he realizes Dumbledore had been keeping this big secret from him. He might also struggle with his identity, feeling torn between the Gryffindor ideals he was raised with and the Slytherin traits he might inherit from Snape.
One idea could be that during the duel, Harry discovers a hidden spell that Snape was about to use against Voldemort. So instead of a full - on fight, they end up in a truce to discuss this new revelation. This could lead to a whole new understanding between them.
A plot could be where a rare and endangered creature chooses Harry and Snape as its protectors. They must travel to different magical locations to find a safe haven for it. This would force them to interact and rely on each other's skills.
Well, you could have a plot where a rare and dangerous pet escapes from the Pet Shop of Horrors and the main characters from Harry Potter have to track it down before it causes chaos in the wizarding world. Maybe there's a pet that can change its form and is being used by a dark wizard to spy on Hogwarts students. Or it could be that a special pet is the key to unlocking a hidden magic in the Forbidden Forest and different characters are vying to get it from the pet shop.
Another idea is that after Snape sacrifices himself, his spirit somehow remains bound to Harry. He becomes a sort of spiritual guide for Harry, like a father figure from beyond the grave. Harry has to learn to communicate with Snape's spirit and in the process, they heal old wounds and form a deep bond.
One idea could be a story where Harry, under the influence of a powerful spell, has to live a day in Severus Snape's memories. He gets to see Snape's childhood, his unrequited love for Lily, and all the sacrifices he made. This would give Harry a new perspective on Snape.