A possible origin story could be that he entered a parallel dimension where vampirism and his spider - powers co - exist. When he returned to his own dimension, he retained some of the vampiric traits, like the fangs. This would open up the story to exploring different dimensions and how they can affect a character's powers and appearance.
Perhaps in the fanfiction, Peter Parker was exposed to a magical artifact that cursed him with vampiric features, such as fangs. Or, it could be that he made a deal with a dark entity in order to gain more power to fight his enemies, and part of the deal was getting fangs. This would add a moral dilemma to his character as he has to deal with the consequences of this deal.
A third storyline could be Peter on a date with MJ. All of a sudden, he has an asthma attack. This could add a layer of vulnerability to their relationship. MJ could be shown as being very caring and helpful, and it could also be a moment where Peter has to be honest about his health condition to someone he cares about deeply.
One possible meaning could be a sign of his individuality. In the world of fanfiction, Peter might use tattoos to set himself apart from the normal, expected image of Spider - Man. It could also represent a new phase in his life, perhaps a more rebellious or self - discovery phase.
One reason could be for added mobility. Wings would allow Peter Parker to move in different ways compared to just swinging on webs. He could fly over obstacles more easily and reach places quicker. Another reason might be for a new look or aesthetic in the story. It gives the character a different visual appeal.
One possible storyline could be Peter Parker's struggle to keep his identity as Spider - Man a secret while dealing with malnourishment. Maybe he's so focused on fighting crime that he forgets to take care of himself. Another could be that due to some financial difficulties, he can't afford proper food, and this affects his performance as Spider - Man. For example, he might be slower or less able to focus during battles.
In some fanfictions, Peter Parker might have the power to control spiders other than just having the abilities of one. For example, he could communicate with all spiders and make them do his bidding, like creating a spider army to fight villains. Another power could be the ability to manipulate his webs in more complex ways, such as changing their texture or making them invisible for stealth attacks.
One interesting story could be where Harry discovers he has fangs due to a dark magic spell gone wrong. He has to hide it from his friends at first, but then they find out and help him find a way to reverse it.
One possible plotline could be Peter struggling to communicate his superhero identity and his daily life challenges to his friends and family without using his voice. Maybe he has to develop a unique sign language or other non - verbal communication methods.
One possible theme is the fragility of life. Despite Peter's powers, his death in fanfiction can show that no one is invincible. It can also explore themes of redemption for other characters. For example, a villain might have a change of heart after Peter's death. There could also be a theme of hope emerging from the ashes of his death, with new heroes rising up.
If such a fanfiction exists, it could be a very dark interpretation. Maybe it's part of a scenario where Peter is in a fight with a villain who has overpowered him and is trying to kill him in this brutal way. Or it could be a non - villain - related situation, like an accident or a misdirected power use by another character, but this is still a very disturbing concept.
One significance could be related to his power. Fangs might symbolize his hidden strength, like his jinchuriki powers. It gives a more visual representation of the beast within him.