Dean would become more protective. His tough - guy exterior would soften as he takes care of the baby. He'd be more cautious in his hunts, not wanting to leave the baby unprotected.
One great fanfiction with this concept is 'Baby Dean's Adventures'. It has a really cute take on how the other characters deal with a baby Dean. They struggle at first but then it becomes a heartwarming story of protection and family.
Well, perhaps the baby is a key to closing a major portal to the underworld. Dean discovers this and has to raise the baby while also preparing it for this great task. Along the way, he gets help from Sam and other friends. They face various challenges from demons who want to stop the baby from fulfilling its destiny.
The relationship between Dean and the idea of a baby is really interesting. It shows a different side of Dean, his protective and nurturing side which we don't always see in the show.
There probably is. The Supernatural fandom is quite large and creative. Some fans might have come up with the idea of Dean having a tail for various reasons, perhaps as part of a magical or cursed storyline. It's worth exploring the major fanfiction hubs to find it.
Maybe Dean gets cursed by a witch. The tail could be a side - effect of the curse that slowly changes him. He has to find a way to break the curse while still hunting monsters, and Sam has to deal with his brother's new 'accessory' and the problems it causes during their hunts.
You can try websites like Archive of Our Own (AO3). It has a large collection of Supernatural fanfictions, including those related to Dean and baby - themed ones. Just use the search function and type in relevant keywords.
Obviously, Dean and Sam are main characters. They are the protective older brothers. And then there's the baby sister, who is likely a central figure as well, with her own personality and role in the fanfiction. There might also be other recurring characters from the 'Supernatural' universe like Castiel who could play important parts in the story.
One great example could be 'Dean's Little Miracle'. In this fanfic, Dean discovers he has a daughter in a very unexpected way. Maybe she was the result of a one - time encounter during a hunt that he had long forgotten. The story then follows how he adjusts to being a father while still dealing with the usual Supernatural chaos.
One interesting storyline could be the baby sister having special powers that she has to learn to control. Maybe she can communicate with spirits in a unique way, different from Sam and Dean, which adds a new dynamic to their hunting adventures.