In a fanfic, Meowth's evolution might be a result of a magical spell gone wrong. Instead of evolving into a normal form, it becomes a hybrid of different Pokemon types. This new form gives it strange and wonderful abilities, like being able to turn invisible or create illusions. But it also has to deal with the confusion of its new identity and how other Pokemon and humans react to it.
One possibility could be that Meowth evolves after a deep emotional experience. Maybe it befriends a Pokémon that is in great danger and through the process of saving it, Meowth unlocks a new level of power within itself and evolves. This could lead to a whole new form with different abilities and a more noble appearance.
It's possible that in the Pokemon fanfic, Meowth is punished by being forced to do tasks it hates. Since Meowth is usually quite mischievous and often up to no good, the author of the fanfic might make it clean up a dirty and stinky place, like a Pokemon waste disposal area. It would be a very demeaning punishment for Meowth, and it would have to endure the smell and the hard work, all while being supervised by other Pokemon who might mock it.
Meowth joining Ash in a fanfiction could also lead to some interesting character development for both. Ash might learn more about the Pokémon world from Meowth's perspective, especially the seedy side that Meowth has been a part of with Team Rocket. And Meowth could learn about friendship and loyalty in a new way, different from what he's experienced with Jessie and James.
One reason could be its loyalty to Team Rocket. In many Pokemon stories, Team Rocket is the bad guy group. So, if Meowth is part of Team Rocket in the fanfic, when they do something really bad like trying to steal a rare and beloved Pokemon from a village, the villagers might catch Meowth and punish it instead of the whole team. They could make it do hard labor, like carrying heavy sacks of Pokemon food around the village all day long. This is because Meowth is more accessible and less intimidating compared to the other members of Team Rocket.
In a fanfic about Meowth evolving, it could be that a powerful enemy forces Meowth to adapt and evolve in order to protect its friends. This evolution might give it new abilities and a different appearance, perhaps more intimidating to foes.
If Meowth evolves, its relationships with other Pokémon could change significantly. For example, Pokémon that used to bully it might now be intimidated by its new form and power. Meowth's old friends, on the other hand, could be proud of it. They might look up to it for protection now. For instance, Pikachu, who was once an equal to Meowth in a sense, might now see Meowth as a stronger ally and be more likely to team up with it in battles.
However, over time, he could develop resilience. The experience of being abandoned might force him to become stronger, both physically and emotionally. He may learn to trust again, but it would be a slow process as he has to overcome the initial emotional trauma of abandonment.
Well, it could be about a Meowth that discovers a special power that allows it to mega - evolve not once but twice. Maybe it goes on a journey to find a way to control this new - found power. Along the way, it meets other Pokemon and trainers who either help or hinder its progress.
In the fanfic, the Mega Mega Meowth could be the center of a mystery. No one really knows how it came to be or what its full capabilities are. Trainers from all over might be trying to study it or capture it. This would create a lot of tension and excitement in the story. The author could also explore how the Pokemon world reacts to such a powerful and unusual creature. Maybe some see it as a threat and some see it as a symbol of hope for new power and evolution in the Pokemon world.
In this fanfic, the plot could be that Meowth has a change of heart after an encounter with a powerful and kind Pokémon that Ash helps. This makes Meowth realize that Ash's way of treating Pokémon is better. So, he joins Ash. He could then use his unique skills, like his ability to talk, to help Ash in battles and communicate with other Pokémon more effectively.