Well, a plot idea could be that the boys are on a mission to find the rarest lemon in the world for a science project. Along the way, they encounter various obstacles like a lemon - loving villain who wants to hoard all the lemons for himself. Or perhaps they turn their lemon - inspired contraption into a vehicle that can fly them to different lemon orchards around the globe. They could also use lemons to create a musical instrument that plays the most beautiful tunes, and they end up performing a concert for the whole town with it.
Here's some plot ideas. Maybe there's a lemon - related mystery in town. All the lemons are disappearing, and Phineas and Ferb suspect it has something to do with a new lemonade factory that just opened. They investigate and find out that the factory's machines are malfunctioning and sucking up all the lemons instead of just using them for lemonade. Or they could use lemons to make a huge, floating lemon - shaped balloon that they use to explore the skies. And they might also find a way to use lemons to make clothes that have a refreshing lemon scent and are super comfortable.
One idea could be that Phineas and Ferb build a lemon - themed amusement park in their backyard. It could have rides made out of giant lemons, and lemonade stands everywhere. Another could be that they use lemons to power a new invention that can travel through time. And a third idea might be that they discover a lemon - based alien species and have to communicate with them using lemon - scented signals.
The OC could be a time - traveler from the future. She comes back to the present to stop an event that will have a negative impact on the future. Phineas, being the curious and adventurous type, joins her on this mission. They use their combined creativity and Ferb's logical thinking to solve the mystery and prevent the disaster.
One idea could be Phineas and Ferb building a time - traveling roller coaster that takes them to different eras in their town's history. They could meet their ancestors and see how things were built and developed. Another plot could be that Doofenshmirtz creates an invention that accidentally swaps the personalities of all the characters. So Phineas becomes super - serious and Ferb becomes overly enthusiastic. It would be really funny to see how they deal with their new personalities while still trying to complete their daily big builds.
One idea could be to explore what happens when Phineas and Ferb build a time - traveling device. They could go back in time and meet their parents when they were kids. Another idea is a story where Perry the Platypus has to team up with Doofenshmirtz's daughter Vanessa to save the day. Maybe they discover a new villain who is more powerful than Doofenshmirtz and they have to put aside their differences to stop this new threat.
One popular theme is time - travel adventures. Fans might write about Phineas and Ferb accidentally creating a time - machine and going back in time to meet their ancestors or visit important events in the history of their town. Another theme could be alternate universes, where things are a bit different in their world, like if they were superheroes or if the animals could talk all the time.
A really cool plot could be that Ferb discovers he has some latent Force - like abilities. Phineas then decides to build a device to enhance these abilities. Meanwhile, in the Star Wars universe, there's a new threat emerging that only their combined skills and knowledge can defeat. They have to travel across different planets, meet various characters, and use their unique brand of problem - solving. Along the way, they introduce some of their friends from their own world to the Star Wars characters, creating some really interesting cultural exchanges and comical situations.
Maybe the little sister gets lost in the backyard which has been magically transformed by one of their inventions into a huge, mysterious maze. Phineas and Ferb then have to use their wits and knowledge of the backyard to find her. It could show their protective side towards their little sister.
One idea could be that Phineas and Ferb build a super - advanced lightsaber - making machine. They use their usual creativity and some 'Doo - hickey' they invented to create lightsabers with unique features like changing colors on command or having the ability to transform into other tools. Ferb could be the one who focuses on the technical aspects while Phineas comes up with the wild designs.
The male oc could be a mysterious musician. He has a unique style of music that Phineas and Ferb are intrigued by. They collaborate to put on a huge music concert in the neighborhood, but they have to overcome obstacles like getting the right instruments and finding a suitable venue. This would involve a lot of musical creativity and problem - solving.
Yes, there are. Some fanfics might focus on the friendship between Phineas and Ferb, or their interactions with other characters like Perry the Platypus. For example, there could be stories about how they solve a mystery in the neighborhood together. You can also look for fan - created crossovers that combine 'Phineas and Ferb' with other family - friendly shows in a non - adult way.
Another interesting OC could be a time - traveling character. This OC could accidentally land in the Phineas and Ferb's world while on a mission in time. Their presence could cause some chaos as they try to fix their time - traveling device, and Phineas and Ferb might end up helping them, leading to an adventure through different eras.