Well, it could be that the fanfiction writer is using Voldemort's pet and Harry's glasses in a really creative way. Maybe the pet has some sort of strange attraction to the glasses. It could be magical in nature. For instance, the pet might be able to see things through the glasses that it can't normally see. Or perhaps Voldemort uses the pet to get to Harry's glasses as a way of taunting him. After all, Harry's glasses are something very personal to him.
In some fanfictions, Voldemort's pet might be used as a symbol of his power and evil. Harry's glasses, on the other hand, are an iconic part of his character. The combination could be used to create a unique plot. For example, Voldemort's pet might steal Harry's glasses to disrupt his vision and thus his ability to fight. It could also be a more symbolic connection, like the pet representing Voldemort's hold over Harry's life, and the glasses being a symbol of Harry's identity that Voldemort wants to break.
Maybe in this fanfiction, Voldemort has a change of heart after making Harry his pet. Without his glasses, Harry appears more helpless, and this could stir some long - forgotten emotions in Voldemort. He starts to see Harry not just as an enemy but as someone he can manipulate in a different way. He could try to groom Harry to be on his side, using a combination of threats and false kindness. Harry, on the other hand, is constantly thinking of how to turn the tables and get back to his friends and the fight against the Dark Lord.
One possible plotline could be that Voldemort's pet somehow steals Harry's glasses as a way to taunt him. This could lead to Harry going on a quest to retrieve them, facing various dark magic obstacles along the way.
The fanfiction could explore a scenario where Harry's glasses are taken away as a way to break his spirit. Voldemort, having Harry as his pet, might want to completely subdue him. Without his glasses, Harry has to navigate a blurry world. This could lead to some interesting interactions with other characters. For example, Hermione might try to find a magical way to restore Harry's vision or at least give him some form of sight assistance without glasses. Ron, on the other hand, could be conflicted about whether to help Harry escape Voldemort's clutches or if he should follow Voldemort's orders as well since Harry seems so different without his glasses.
It could be that the pet is magically attracted to the glasses. Maybe the glasses have a certain charm or power that the pet senses, and it tries to steal them to bring back to Voldemort. For example, if the glasses can see through certain dark magic disguises, Voldemort would want to get his hands on them through his pet.
The pet could try to break Harry's glasses. Since Voldemort hates Harry, his pet might be programmed or trained to destroy things that are important to Harry. The glasses are a very visible and important part of Harry.
Harry would likely be defiant at first. Even without his glasses, he has his inner strength. He would probably try to resist Voldemort's every command and look for opportunities to escape or fight back.
In some Harry Potter fanfictions, Voldemort's pet could be a large and menacing snake, like Nagini. Since snakes are often associated with Slytherin and Voldemort was a descendant of Slytherin, it makes sense for his pet to be a snake. It could also be some sort of dark magical creature, perhaps a basilisk under his control. Another possibility is a magical raven or crow, which could be used as spies for him, flying around Hogwarts and other places to gather information.
Perhaps Voldemort uses magic to brainwash Harry into thinking he is his pet. Harry then has to fight against this false identity while still being under Voldemort's control. The plot could involve Harry slowly regaining his true self and using his new - found knowledge of Voldemort's inner workings (from being so close to him) to defeat him in the end. It would be a journey of self - discovery and resistance.
Well, it might be a dark magical creature that is not from the normal wizarding world. For example, a shadowy beast that can move through walls and is almost invisible. This pet could be used by Voldemort to terrify his enemies and deliver secret messages.
It could be that Voldemort's pet Harry is actually a form of psychological warfare for Voldemort. He wants to break Harry's spirit completely. However, Harry uses this situation to his advantage. He befriends some of the dark creatures that Voldemort has around his lair, and with their help, he manages to create chaos and confusion, which in turn gives the Order of the Phoenix an opportunity to strike at Voldemort.