Another plot could be a time - travel one. Toffee Star goes back in time to prevent a certain event that led to the current state of conflict with The Forces of Evil. Along the way, they meet younger versions of the characters from The Forces of Evil and have to convince them that they are not the enemy, all while trying to change the course of history.
One interesting plot idea could be that Toffee Star, having some hidden powers, teams up with an unexpected character from The Forces of Evil. Maybe a character who was once an enemy but now they have a common goal. For example, they both want to stop a new, greater evil that is emerging in their world. This could lead to a lot of character development as they learn to trust each other.
A plot where Toffee Star gets trapped in a magical realm created by The Forces of Evil. In this realm, the rules are different, and Toffee Star has to use their wits and unique abilities to escape. As they try to find a way out, they start to understand the motives behind The Forces of Evil's actions better, which could lead to a potential truce or a new alliance in the future.
Perhaps in the fanfiction, Toffee's memories are transferred into Star's mind. Star then has to deal with not only her own thoughts but also Toffee's memories and emotions. This could lead to her making decisions that are influenced by Toffee, which confuses her friends and family. She has to find a way to separate Toffee's memories from her own without losing her own identity in the process.
It could be one of Toffee's old allies who was in the shadows before. Maybe someone who was just as power - hungry as Toffee but was waiting for the right moment to strike. Another option could be a corrupted form of a character we already know, like a dark version of Marco. He could be turned against Star by some dark magic.
Well, a cool plot might involve a mermaid princess in the Star vs the Forces of Evil world who is in love with Marco. Star helps her to win Marco's heart in exchange for some magical mermaid artifact that can help Star in her fight against the forces of evil. Or perhaps there's a mermaid coven that has been cursed by Ludo's family long ago, and Star has to break the curse to gain their allegiance against the ever - growing forces of evil.
Perhaps a plot where the forces of evil from both universes join together. Ben and Star have to form an alliance with their respective friends and family. They must learn about each other's powers and strategies to defeat this combined evil. Ben might teach Star about his alien tech, and Star could show Ben how to use magic in combat.
One idea could be that Eclipsa discovers a new, hidden power within herself that gives her an edge against the forces of evil. Maybe it's a long - lost spell from her ancient lineage. Another could be a team - up between Eclipsa and some unexpected allies from different realms to fight the forces of evil.
A great plot idea could be that Eclipsa discovers a hidden power within herself that is both a blessing and a curse. She has to figure out how to control it while also dealing with the politics of Mewni. Another could be a time - travel fanfiction where Eclipsa goes back to key moments in Mewni's history to change things for the better. And one more idea is that Eclipsa starts a school for different kinds of magic, which causes a stir among the traditional magic users in Mewni.
Well, a plot could revolve around Marco and Star dealing with the reactions of their friends and family to the pregnancy. Some might be overjoyed, while others could be worried about the challenges ahead, like how they'll balance their duties and raising a child in a world full of magical threats.
Another interesting plot could be about a character who discovers an unexpected side - effect of the 'Cleaved' event. Maybe there are new powers emerging or a hidden danger that only they can sense, and they have to convince others to take action.
One idea could be that Star discovers a magical gaming console in the Magic Realm. This console has games that are actually portals to different dimensions. She and Marco could team up to complete the levels in the games to save these dimensions from an evil force that is spreading through the gaming portals.
Well, perhaps a plot where hypnosis is used to make the characters switch personalities. For example, Star becomes very timid and cautious instead of her bold self, and Marco becomes overly confident. They then have to navigate their daily challenges in this reversed state until they can break the hypnosis. This would lead to a lot of comical and also some heartfelt moments as they learn about themselves and each other in new ways.