Well, I haven't come across a 'harry is a severus son bat wings' fanfiction directly. However, when looking for it, keep in mind that the 'bat wings' part might be a very specific and perhaps a bit of a strange addition. Fanfictions often explore unique and unexpected ideas. Check the tags and summaries carefully on fanfiction platforms. Some writers might use symbolic or metaphorical meanings for the 'bat wings' in relation to the relationship between Harry and Severus.
In 'harry calls severus papa bat fanfiction', there is a strong focus on character development. Harry may grow to be more understanding and less impulsive as he forms this bond with Severus. Severus, on the other hand, might become more open and less bitter. The fics may also introduce new plotlines that revolve around this relationship, such as them working together to solve a new magical mystery that is related to their family - like connection.
It could be a dark wizard who has the power to control bats and uses them for evil purposes. He might be trying to take over Hogwarts using his bat minions.
There are likely fanfictions that explore Harry Little Bat's origin. It could detail how he came to be in his current situation, his family's history, and any special abilities he might have inherited. Some stories might also put him in an alternate universe where the rules are different. For example, he could live in a world where bats are the dominant species and he has to deal with the responsibilities that come with that. There could also be a story about his first flight and the emotions he experiences during that moment.
In a 'harry is a severus son bat wings' fanfiction, the plot might start with Severus being in a difficult situation where he discovers he has a son, Harry, with an unusual feature - bat wings. Harry could be bullied at Hogwarts because of his wings. Severus, on the other hand, tries to teach Harry how to use his wings to his advantage. There could be a sub - plot about a dark wizard who wants to capture Harry to study his wings for some evil purpose. Harry and Severus would then have to team up, using their combined knowledge of magic and Severus's skills as a potions master to defeat the dark wizard and protect Harry's secret.
It could be special because it introduces the unique world that Inspector Harry Hole inhabits. This first novel might have a distinct atmosphere and set of characters that draw readers in. For instance, it might have a really interesting and shadowy cityscape as the backdrop for the story. Also, the way the author portrays Harry Hole's investigative skills and his inner thoughts could be what makes it stand out.
A 'little bat' can play the role of a messenger. In the Harry Potter world, owls are the common messengers, but a little bat could be a more secretive option. It could carry small, important notes between characters who don't want their communications to be easily noticed.
Well, perhaps there's a fanfic where Dumbledore travels to the Muggle world for some reason and stumbles upon a baseball game. He gets hold of a baseball bat and realizes it has some interesting properties. Back at Hogwarts, he uses magic to enhance the bat and it becomes a sort of magical weapon that can be used against dark forces. Maybe it has the power to deflect dark spells or even send out bursts of positive energy. And the students are both amused and amazed by this new addition to Dumbledore's arsenal.
I'm not sure of a specific 'harry calls severus papa bat fanfiction' title off the top of my head. But you can try searching on fanfiction - dedicated websites like Archive of Our Own. There are usually many fics with this kind of interesting relationship exploration, and you can filter the results by tags and ratings to find the ones that suit your taste.
I'm not sure specifically as the title seems rather unclear and perhaps misphrased. It might be a very unique or indie novel. Without more context, it's hard to say what it's about.