One idea could be a story where the phantom has a protective instinct towards the baby. Maybe the phantom is a misunderstood entity and the baby is the only one who isn't afraid of it, so it decides to safeguard the little one from all the evils in its spooky world.
Well, it could be a fanfic where the phantom and the baby have a special connection through dreams. The baby is constantly visited by the phantom in its dreams and they form an unbreakable bond. As the baby grows, this bond starts to have an impact on the real world, like the phantom being able to guide the baby in some way.
Well, for Danny Phantom baby fanfiction, you could write about Danny having to babysit a baby that has the ability to see ghosts like he does. It would be full of comical moments as Danny tries to keep the baby calm while also dealing with ghosts. Or perhaps a story where Danny discovers a baby ghost in the Ghost Zone and decides to bring it back to the human world to protect it. You could also write a story where Danny's parents find a baby with strange energy readings and Danny has to keep his identity a secret while trying to figure out what's going on with the baby.
One idea could be that Elijah discovers a lost baby and decides to protect it at all costs. He might use his skills and resources to keep the baby safe from various threats in a fantastical world.
One interesting idea could be the origin of the ectoplasm baby. Maybe it was created accidentally by Danny during one of his ghost - fighting adventures. Another idea could be the baby having unique powers that are a mix of Danny's ghost powers and something new related to the ectoplasm. For example, it could have the ability to manipulate ectoplasm in ways Danny can't.
One idea could be that Danny's ghost powers somehow lead to an unexpected pregnancy situation for a female character, and then he has to deal with the responsibilities of being a 'baby daddy' while still keeping his ghost - fighting a secret. For example, maybe a new ghostly enemy targets the unborn child.
One idea could be a fanfic where Danny discovers a new power that has unexpected consequences. For example, he might gain the ability to time - travel and has to deal with the chaos it causes in the timeline. Another idea is a fanfic that focuses on Danny's relationships in the ghost zone. Maybe he forms an alliance with a powerful but misunderstood ghost. A third idea could be a story where Danny has to go undercover as a human in a place full of ghosts who don't know he's half - ghost.
The relationship can start with curiosity. The baby might be intrigued by the strange presence of the phantom and the phantom, in turn, is fascinated by the baby's innocence. This initial interest can gradually grow into a deep bond as they spend more time together, even if it's in a very unusual way like the phantom appearing only at night.
One idea could be that Danny and Randy have to team up to stop a powerful ghost - ninja hybrid villain. Their unique powers combined could make for some exciting battles and problem - solving. For example, Danny could use his intangibility to avoid attacks while Randy uses his ninja skills to strike back.
One plot idea could be that baby Danny accidentally wanders into Vlad's lair. Vlad, instead of being his usual villainous self, is surprisingly gentle. He realizes that Danny's innocence might be a chance for him to change his ways. Maybe he tries to mentor Danny in a different, more positive way, teaching him about his ghost powers in a non - malicious manner.
A plot could be that a magical spell gone wrong makes Sam and Danny age down to babies. Tucker discovers that there's a time limit to reverse the spell. Meanwhile, the two babies are exploring the world in a very different way, seeing things from a new perspective. This could lead to some heartwarming and funny interactions with their families and friends as they all try to solve the mystery of the spell.
One interesting aspect could be the unique character interpretations. In fanfics, authors often explore different sides of Danny Phantom's personality. Maybe in 'baby steps' they show his more vulnerable or developing side as he takes small steps in his adventures or personal growth.