In this form, Jack's personality would change significantly. He would lose some of his cocky and self - assured nature. Instead, he would be more dependent on others. Since he's in a baby form, he would be more trusting, which is different from his normal guarded self. He might also be more emotional, crying easily when things don't go his way or when he misses his friends. His sense of humor would probably still be there but in a more child - like way, like finding simple things like a shiny pebble extremely fascinating and funny.
Well, Jack as a baby pooka would be a lot more vulnerable, which would make his personality more timid. He wouldn't have the same confidence to take on challenges like he usually does. His mischievous side might still be there but in a much cuter and less calculated way. For example, instead of planning elaborate pranks, he might just accidentally cause a little chaos by being clumsy. He would also be more affectionate, seeking out hugs and cuddles from those around him, which is a big change from his more independent self.
Jack's personality would likely become more innocent and naive. As a baby pooka, he might be more curious about the world around him without the usual wariness he has as his normal self. He could be more easily frightened by things that he wouldn't normally be afraid of as an older Jack. Also, he might be more impulsive in his actions, just going for things that catch his eye without thinking much about the consequences.
The plot might be that Pitch has a new plan to create chaos. He discovers that turning Jack into a baby pooka can disrupt the order of the magical world. Once Jack is transformed, he is found by a group of friendly forest spirits. These spirits don't know who Jack really is at first but take him in. As time passes, Jack starts to show some of his old abilities in small ways, like being able to create a tiny bit of frost. This catches the attention of the Guardians who then start to investigate. They eventually figure out it's Jack and have to fight Pitch to get the antidote to turn Jack back.
Perhaps in this form, Jack Frost is befriended by a young human child. The child doesn't realize he's Jack Frost and just thinks he's a really cool and strange little animal. They go on adventures together in the winter wonderland, with Jack Frost using his powers in small, unnoticeable ways at first.
The plot could center around Jack Frost being cursed into his baby pooka form by a mischievous winter spirit. He then has to find a way to break the curse. Along the way, he meets other magical beings who either help or hinder him. For example, a snowman he created in his normal form might come to life and guide him to a magical crystal that has the power to reverse the curse.
They would become more united. Having a baby would make them a family, and they would support each other more closely in taking care of their child.
One interesting story could be about Jack Frost teaching Baby Pooka how to create unique ice sculptures. In this fanfiction, Jack Frost uses his powers over ice and snow to show Baby Pooka the beauty of his creations. Another could be a story where they team up to save their magical realm from an encroaching darkness. They use their individual abilities, Jack's cold powers and Baby Pooka's special skills, to fight off the evil forces.
It's possible that his powers would be more erratic. As a baby, he doesn't have the control he has as an adult. So, his ice - making abilities might go off randomly. For example, he could accidentally freeze the water in a nearby pond just by being near it while having a little tantrum. But as he grows and learns about his powers again, he would start to gain more control over them.
Jack could use his ice powers to create a distraction. For example, he could make a large ice structure that startles Pitch and gives Jack a chance to run. Another way is if he can find Pitch's weakness. Maybe Pitch is afraid of a certain light or sound, and Jack can use that to his advantage to escape.
Pitch might comfort Jack by simply being there for him. Just his presence can make Jack feel less alone.
You can start by looking on popular fanfiction websites such as Archive of Our Own (AO3). It has a wide variety of fan - created content, and you can search specifically for Jack Frost and Baby Pooka stories using the search function. Another option is FanFiction.net, which also has a large collection of fanfiction, though the tagging system might be a bit different.
Naruto's normally sunny and optimistic personality would likely become darker. He might be more brooding and less quick to trust. His sense of humor would probably take on a more sardonic edge as the power of Jack of Blades seeps into him.