One way to write it uniquely is to focus on the magical or supernatural aspects of Stevonnie's pregnancy. Since they are a fusion, there could be some extraordinary things that happen during the pregnancy that are related to their gem powers. For example, the baby could have some sort of gem - related ability even before birth.
Use the pregnancy as a symbol. It could represent a change in Pennywise's nature or a new phase in its existence. The story could be about Pennywise's journey of self - discovery through this pregnancy. It could question its own identity as a bringer of fear now that it is about to bring new life into the world. This would add depth to the fanfiction and make it stand out from more typical horror - based stories.
Perhaps in the fanfiction, Stevonnie could face challenges from society. Since they are a rather unique being, there might be prejudice or misunderstanding about their pregnancy. They would then have to fight for their right to have and raise their child in a positive environment. Also, the relationship between Stevonnie and their partner (if there is one in the fic) could be explored deeper as they navigate this new chapter of their life.
Another approach is to make it a more serious, in - depth exploration of identity. Anakin is already a complex character. His pregnancy could force him to re - evaluate his role not just as a Jedi, but also as a potential parent. It could be a story about him coming to terms with a new part of himself that goes against the norms of his society and his own understanding of his body and purpose.
It can focus on the support system they build. For example, showing how their friends come together to help them with baby stuff or just be there for emotional support.
You could incorporate the magic of the Harry Potter world into his treatment. Maybe there are some rare potions or spells that could potentially help, but they come with their own risks and side - effects. For example, a potion that might slow the cancer but also makes him lose his ability to use magic temporarily. This would create a great conflict within the story.
You could write it so that Jacob Black time travels as a side - effect of a powerful spell cast by an old Native American shaman. This would tie in with his Native American heritage and add an element of mystery and magic specific to his world. He might then be sent on a quest in the different time period he lands in.
It could be written from the perspective of how the other characters react. Hermione would likely be very scientific about it, trying to find a way to reverse it while also being supportive. Ron might be a bit more shocked and clumsy in his support. And Dumbledore could be the wise figure, guiding Harry through this strange time, perhaps having some hidden knowledge about such a phenomenon from the past of Hogwarts.
Naruto could have a snake summoning contract instead of toads. This would completely change his combat style and the types of allies he has. He could summon different kinds of snakes with various abilities like poison, constriction, or even the ability to fly.
Well, fireworks can be used as a symbol. For example, in a fanfiction, every time Batman has a major victory, the people of Gotham set off fireworks. It becomes a sign of hope. Or, a new villain could create fireworks that are actually small bombs disguised as regular ones. Batman has to quickly learn to tell the difference to stop the villain's attacks.
You can make it unique by adding a different time period setting. For example, set it in a future where technology has advanced and there are new ways to deal with a male turtle's pregnancy.