Well, there could be a plot where Harry Potter, as the Doctor's son, discovers a whole new side of the wizarding world. Maybe the Doctor has some kind of influence on the magic in Harry's world. For example, the Doctor's technology could interact with magic in unexpected ways. Harry could also have adventures across different universes, using both his magic and the Doctor's time - travel skills. He might meet other characters from both the Harry Potter and Doctor Who universes and form new alliances or face new enemies together.
In a fanfiction where Harry Potter is the Doctor's son, a plot could revolve around Harry's identity crisis. He has grown up in the wizarding world, but now he discovers he has this whole other heritage. This could lead to him feeling out of place in both worlds. Maybe he tries to hide this fact from his friends at Hogwarts at first. There could also be a plot where the Doctor finally reveals himself to Harry and takes him on adventures through time and space. Along the way, they could encounter ancient magic and alien species, and Harry would have to learn how to balance his wizarding skills with his new - found abilities as the Doctor's son.
One possible plot could be that Harry inherits the Doctor's time - traveling abilities. He could use them to go back in time and prevent some of the tragedies in the Harry Potter world, like the death of his parents. Another plot could be that the Doctor's enemies target Harry, thinking they can use him to get to the Doctor. And Harry has to learn about his true heritage and how to use his new - found powers to fight back.
One challenge could be the clash of cultures. The wizarding world has its own set of rules, traditions, and magic, while the Doctor Who universe has time - travel, different species, and advanced technology. Harry would have to navigate between these two very different worlds. Another challenge might be acceptance. In the wizarding world, he's known as a wizard, but in the Doctor Who world, he'd be the Doctor's son, which might bring different expectations.
One possible plot could be that the son is lost in a strange dimension that combines elements of the Harry Potter world and Loki's world. Harry Potter and Loki have to team up to find him. Along the way, they face various challenges like magical creatures from the Potterverse and Loki's enemies. The son, when found, might have developed some unique powers that are crucial for saving both their worlds.
It depends on the specific fanfiction. Some fanfiction authors love to create crossovers and come up with really strange and interesting relationships. So there could be a fanfiction where Harry Potter is made out to be the Doctor's son. But if we look at the official storylines of Harry Potter and Doctor Who, this relationship doesn't exist. Fanfiction gives a platform for fans to play with ideas like this, to create new storylines that might shock or amuse other fans.
Well, one possible plot could be a wizard who has picked up the Muggle habit of smoking cigarettes and how it affects his magic. Maybe his spells start to go awry because the smoke interferes with the magical energy. Another could be a group of Hogwarts students who discover cigarettes in the Forbidden Forest and have to deal with the consequences of this Muggle item in a magical place. But these are just very speculative ideas as it's not a common type of fanfiction.
Perhaps there's a fanfiction where Ron is forced to work at a dentist's office as a punishment. He has to deal with all kinds of strange patients, from veelas with very sharp teeth to giants with massive molars. His misadventures in the dentist office, trying to use magic to get out of his work or accidentally making things worse, could make for a really funny and engaging plot.
A 'Harry Potter train's alone' fanfiction could have a plot where the train is abducted by a powerful dark force. The train has to fight back using its own magical properties. It could call on the spirits of the railway tracks or the magic of the surrounding forests to help it. Or perhaps the train discovers that it has a long - lost sibling in the form of another magical vehicle, and it goes on a quest to find it while being alone.
Well, perhaps the plot could involve Harry being raised as a Malfoy heir. He would be taught the pure - blood ideology from a young age. But as he goes to Hogwarts, he starts to question these beliefs. There could also be a plot where Lucius has some hidden motive for having Harry as his son, like using Harry's connection to Voldemort for his own gain. And Harry has to figure out his place in this web of lies and power plays.
One possible plot could be Harry's struggle to keep his werewolf identity a secret from his friends at Hogwarts. He would constantly be in fear of discovery during the full moon.
Well, it could be about Harry having the Doctor's knowledge and skills. Maybe he uses time - traveling abilities from the Doctor to change events in the wizarding world. For example, he could go back in time to prevent some of Voldemort's early evil deeds.
A possible plot might be that Harry uses his Superman - like powers to help the wizarding world during times of peace as well. For example, he could use his super strength to rebuild parts of Hogwarts that were damaged in previous battles. Or he could use his flight to quickly transport important magical artifacts from one place to another. Also, there could be a plot where the wizarding community is initially afraid of Harry because of his non - magical powers, but he has to prove that he is still one of them and is there to protect them.