Well, one possibility is that he could be taken in by a kind family. They might not know who he really is and just think he's an ordinary baby. They would care for him, feed him warm milk, and keep him cozy in a little crib. As he grows up, he might start to show signs of his magical powers, like making little ice crystals form on his crib railing when he's excited or sad.
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.
One idea could be that Jack Frost turns into a human to experience the warmth of human emotions. He might find himself in a small town during winter. As a human, he discovers the joy of a hot drink on a cold day, something he never truly understood as a spirit. He could also fall in love with a local girl who is kind - hearted and loves the winter. This newfound love makes him question whether he wants to return to his former state or stay human forever.
Obviously, Jack Frost is the main character as the story is about his transformation into a dark version of himself. But there could also be other characters from the original Jack Frost lore, such as the Guardians like North, Bunny, and Tooth. They would likely play important roles, either trying to save Jack from his dark path or being forced to oppose him if he becomes too dangerous.
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.
Well, at first, Jack Frost as a human might be very confused. He could be disoriented by all the new sensations and the lack of his ice powers. But as time goes on, he might start to appreciate the simple pleasures of being human, like the warmth of a hug or the taste of hot chocolate.
Another plot could involve Jack Frost being lured into the darkness by an external force, like a shadowy entity. This entity might promise him more power and control over his existence. As he succumbs to it, his appearance could change, his eyes turning a deep, cold black, and his ice becoming darker and more dangerous. His personality would shift from the carefree spirit we know to a brooding and vengeful being.
Well, perhaps a power - hungry wizard from a neighboring magical realm. He hears about the baby's unique powers that combine Jack Frost's and Elsa's abilities and wants to harness that power for his own evil plans. Or it could be a group of dark fairies who are envious of the baby's special connection to both the winter world and Arendelle. They might try to kidnap the baby and raise it to be on their side, away from Jack and Elsa.
The main characters are obviously Jack Frost and Baby Tooth. Jack Frost is often depicted as a fun - loving, mischievous spirit of winter. He has the power to control ice and snow. Baby Tooth, on the other hand, is a tooth fairy. She is very small and cute and has a big role in collecting teeth from children. In fanfiction, they usually interact in various ways, like going on adventures or just having friendly chats.
If we're talking about a fanfiction where Elsa and Jack Frost have a baby, there are so many storylines that could develop. The baby could be a key to uniting different magical realms that are related to winter. It might face challenges growing up, such as being accepted in both Elsa's world and the world where Jack Frost belongs. The baby's powers could also be a source of both wonder and danger. For example, if it couldn't control its powers properly at first, it could accidentally cause blizzards or freeze things in inappropriate places. But with the love and guidance of its parents, it could learn to use its powers for good and become a beloved figure in the winter - themed magical world.