Another plotline could involve Shadow's own memories in his baby form. He might still have some of his old self - awareness, but in a very limited way. His friends could try to communicate with him, and as he grows up again in the story, he might have a different perspective on things. This could lead to character development and changes in his relationships with other characters in the story.
One possible plotline could be that his friends or allies have to take care of him in his baby form. They might struggle with things like feeding him, changing his diapers, and keeping him out of trouble.
Maybe there's an enemy or a strange magic that turned him into a baby as part of a plot to weaken him. So, his friends not only have to deal with his baby state but also figure out how to reverse the transformation and stop the bad guys at the same time. There could be a lot of comical moments as well as some serious challenges in this kind of plot.
A great plotline could be the mystery behind who turned Hermione into a baby. It could be a dark wizard trying to stop her from achieving something in the future. As a baby, Hermione might start showing some unusual magical abilities that she didn't have before, which could attract the attention of both good and bad forces in the wizarding world. And her friends would be in a race against time to protect her and find a way to turn her back.
I'm sorry, I'm not sure of a specific 'Shadow gets turned into a baby' fanfiction off the top of my head. You could try searching on fanfiction websites like Archive of Our Own. There might be some creative works there that explore this interesting concept.
Perhaps it's a prank gone wrong. A group of Gryffindors, thinking they could teach Draco a lesson, cast a spell on him that they thought would just embarrass him. But instead, it turns him into a baby. Now, Hermione, being the brilliant witch she is, feels responsible for finding a cure. She starts researching in the library, while Ron is left to keep an eye on baby Draco. Ron has no idea how to take care of a baby, and there are lots of comical moments as he tries to feed Draco and keep him from crying.
Well, in such a fanfiction, probably Batman's sidekicks would have to take care of him. They'd be in a really strange situation, having to protect a baby Batman from the villains who might see this as a great opportunity to get rid of him once and for all.
Well, in such a fanfiction, Naruto would probably be really cute as a baby. His friends might be super confused at first. Sasuke might be a bit less brooding towards baby Naruto. And Iruka-sensei would probably take on a more parental role, making sure baby Naruto is safe and cared for.
Maybe it starts with a strange magical experiment gone wrong in Hogwarts. Harry is curious and gets too close, and suddenly he's a baby. The story could then focus on how the teachers, especially Dumbledore, deal with this situation. They might try to figure out if this is a new form of dark magic they haven't seen before. And Harry, as a baby, would have no memory of who he is, so it could also be about his friends trying to make him remember bits of his past life.
One interesting plotline could be Natsu trying to adjust to the new physical form while still having the same adventurous spirit. For example, Natsu might initially struggle with wearing different types of clothes that are more suitable for a female body. Another plotline could be how Natsu's friends react. Some friends might be shocked at first, but then quickly accept and help Natsu through this strange transformation. There could also be a plotline where Natsu discovers new abilities or sensitivities that come with being in a female form.
One interesting plotline could be Bella's struggle to control her new vampire instincts while still maintaining her relationships with her human friends and family. For example, she might have a hard time being around them without revealing her new nature.
Well, there could be a plotline where Castiel in dog form gets adopted by a family. He has to balance living as a normal dog in a human household while also trying to figure out how to reverse the spell or whatever caused him to turn into a dog. This could involve him protecting the family from supernatural threats that they are unaware of, all while being a cute furry companion.
Perhaps there's a plotline where the transformation into a ferret has some unforeseen side effects. For example, Harry might gain some ferret - like abilities such as enhanced sense of smell or speed, which he then uses to his advantage in solving a mystery or escaping from a dangerous situation in Hogwarts. He could also struggle with some of the more ferret - like instincts, like being tempted to hoard shiny objects.