One idea could be that Cosmo and Tails work together to build a new type of spaceship. They use their combined knowledge of mechanics and botany. Cosmo might contribute with her understanding of plant - based energy sources, while Tails uses his engineering skills. Another plot could involve them exploring a mysterious new planet where they encounter strange creatures. Cosmo could communicate with the planet's plant - like life forms, and Tails would figure out how to navigate the terrain.
A possible plot is that Cosmo's mind gets linked to Tails' in an accident. As a result, they start experiencing each other's memories and emotions. This leads to some comical situations like Tails suddenly having an urge to water plants all the time because of Cosmo's love for them. They then have to find a way to unlink their minds while also learning more about each other on a deeper level.
They could be in a situation where a powerful enemy is threatening the universe. Cosmo and Tails use their mind - power (maybe a new power they discover together) to create a shield around the planets. They travel from planet to planet, gathering different elements and knowledge to strengthen the shield. Along the way, they face challenges and make new friends who help them in their mission.
Another plot could involve the daughter going on a journey to learn more about her parents' past. Along the way, she meets different characters who knew Tails and Cosmo. This journey of self - discovery also helps her to understand her own place in the world and her unique abilities.
One plot idea could be that they face challenges in preparing for the arrival of their baby. Maybe they have to deal with threats from villains in the Sonic universe who see their unborn child as a potential weapon or a way to manipulate them.
One idea could be that Cosmo and Wanda's baby discovers a new magical power that no other fairy has. For example, the power to turn inanimate objects into living, talking creatures. This could lead to all sorts of adventures as the baby tries to control this new power and the chaos it causes in the fairy world.
Maybe Cosmo was turned into a different form, like a small, helpless creature. Tails stumbles upon her in this state while on a routine exploration. At first, he doesn't recognize her, but as he gets closer, he realizes it's Cosmo. He then devotes all his time to finding a way to turn her back to her normal self. Along the way, they form a deeper bond, and when she finally returns to her original form, it's a beautiful reunion.
The cuteness factor makes it interesting. Tails is an endearing character and Cosmo is also very likeable. The idea of them having a tickle - related interaction adds a touch of playfulness and light - heartedness to their relationship.
One interesting storyline could be about Tails and Cosmo going on an adventure to discover a new power source for their world. They might face various challenges and enemies along the way.
One interesting scene could be when Tails first sees Cosmo in her wedding dress. His eyes would widen in awe and his cheeks might turn a bit red. Another scene could be the exchange of rings. Since Tails is so inventive, he might present Cosmo with a ring that has some unique function, like a small tracker so he can always find her. And then there's the first dance. With Tails' agility and Cosmo's grace, they could perform a dance that amazes all the guests.
Maybe in the fanfiction, the three - tailed beast crosses over into a modern - day human world. People initially fear it, but then they discover that it has a gentle side and is actually trying to find its way back home. It could form a bond with a group of humans who help it on its journey, leading to many adventures along the way.
One idea could be exploring the origin of the Ten - Tails in a different light. Maybe it was created by an ancient civilization for a noble purpose that got corrupted over time. Another could be a story where a young ninja discovers a hidden power within the Ten - Tails and has to learn to control it without being consumed by its dark energy.
One idea could be that Fluttershy discovers Tails' mechanical skills and they work together to build a special sanctuary for injured animals in both their worlds. This would combine Fluttershy's love for animals and Tails' engineering prowess.