One possible plot could be that Godzilla somehow arrives in the Pokemon world. The Pokemon trainers initially see Godzilla as a huge threat and try to battle it with their strongest Pokemon. But then they realize that Godzilla is not there to cause chaos but is being chased by some powerful and evil force from its own world. So, the trainers and their Pokemon team up with Godzilla to fight this common enemy. This would involve epic battles between the combined forces of Pokemon and Godzilla against the evil force, with lots of strategy and unique power combinations.
The Pokemon characters would likely be in awe or fear of Godzilla at first. Smaller Pokemon might hide behind their trainers or larger Pokemon companions. Trainers, being the more inquisitive ones, would try to assess Godzilla's intentions. Some brave trainers might approach Godzilla with caution, trying to communicate using their Pokemon's abilities like telepathy or by using signs. Godzilla, on the other hand, might not understand the Pokemon world's rules and customs at first and could accidentally cause destruction while just moving around.
Once upon a time, in a strange new world where the boundaries between reality and fantasy were blurred, Godzilla emerged into the Pokemon universe. Pikachu was the first to sense the great beast's arrival. The electric mouse Pokemon was both terrified and curious. Godzilla, on the other hand, was confused by this new land filled with small, strange creatures. As he stomped through the forest, he accidentally knocked down a nest of Pidgey. The Pidgey were angry and began to attack Godzilla, but their small beaks and feathers did little to harm the giant. Meanwhile, trainers from all over the region came to see what was causing the commotion. One brave trainer decided to try and capture Godzilla with a Pokeball, but it was immediately destroyed by Godzilla's atomic breath.
A possible plot could be that Godzilla is accidentally teleported into the Pokemon world. The Pokemon trainers think he is a new, extremely powerful and dangerous 'Pokemon'. So they try to stop him. But as they try to fight Godzilla, they realize that their normal attacks have little to no effect. Then, a group of legendary Pokemon, such as Arceus and Lugia, decide to communicate with Godzilla. They find out that Godzilla is just as confused as they are about this new world. Together, they try to find a way to send Godzilla back to his own world while also dealing with the chaos that his presence has caused in the Pokemon world, like disrupted ecosystems and panicked Pokemon.
Another concept is that Godzilla somehow ends up in the Rosario Vampire universe. This causes chaos as the local creatures and humans are not used to such a huge and powerful being. The main characters from Rosario Vampire then have to figure out a way to either send Godzilla back to his own world or find a way for him to co - exist in theirs.
One interesting aspect is the potential for character development. For instance, a Pokemon that was previously timid might become brave when facing Godzilla. Also, the different environments in the Pokemon world can add new challenges for Godzilla. The forests, mountains, and cities in the Pokemon world can all be used in unique ways in the fanfic. For example, a water - type Pokemon might use a large lake in the Pokemon world to its advantage against Godzilla.
One possible Pokemon Godzilla fanfic could be about a group of trainers who accidentally stumble upon a Godzilla - like Pokemon in a hidden, uncharted region. This Pokemon could have the immense power of Godzilla, causing chaos and also attracting the interest of both good and bad organizations within the Pokemon world. The trainers then have to decide whether to try and capture it or find a way to calm it down.
In a Star Wars Godzilla fanfic, Godzilla could be seen as a powerful force of nature in the Star Wars galaxy. He might be mistaken for a new kind of Sith - created monster at first. But then some characters realize he's not influenced by the dark side. They could try to communicate with him or at least find a way to co - exist. For example, the Ewoks might see him as a giant protector spirit and try to help him.
One interesting concept could be a Godzilla crossover with other giant monster franchises like King Kong. It could lead to epic battles and new storylines where they have to team up or fight over territory. Another concept might be a crossover with a superhero universe. Imagine Godzilla facing off against the Avengers or Justice League, which would require different strategies from both sides.
It could be about Godzilla emerging in the world of Evangelion. Maybe the Angels in Evangelion are confused by this new giant monster. The Eva pilots might have to deal with both Angels and Godzilla at the same time.