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.
One possible plotline could be that it's the result of some strange magic or alien technology. Maybe an enemy uses a device on Goku as part of a plan to weaken him or create chaos. Another could be a more comical take where Goku accidentally ingests something that causes this unusual situation.
Maybe in the fanfiction, Ash is given a Chespin by a mysterious trainer. This Chespin has some special powers that Ash has to figure out how to unlock. As they train together, they form a deep bond and go on to compete in a big Pokémon tournament where Chespin's unique abilities give them an edge.
Another plotline might involve Naruto being ostracized because of his new Mokuton power. Since it was associated with the Uchiha and Senju in a complex way, some in the ninja world might suspect him of having ulterior motives. This would lead to Naruto having to prove himself all over again, this time not just as a jinchuriki but also as a wielder of Mokuton.
A plotline might involve Ash being betrayed by a new acquaintance he meets on his journey. This person could pretend to be his friend, gain his trust, and then use that trust to steal his Pokémon or important items. Or perhaps Ash is betrayed by a Pokémon he just caught. The Pokémon could have been planted by an enemy trainer to spy on Ash and then turn on him at a crucial moment.
In some 'ginny gets drunk fanfiction', the plot might revolve around Ginny being in a new and unfamiliar environment where she gets drunk. This could lead to her exploring a different side of herself. She might meet new people and form new relationships while in this state. The story could then be about how this one drunken night changes her perspective on certain things or people in her life. It could also show her growth as a character as she learns from the experience of getting drunk and the events that follow.
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.
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.
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.