Well, a frequent theme is adaptation. Godzilla has to adapt to the bright and friendly world of the ponies, and the ponies have to adapt to the presence of a huge, potentially dangerous monster. Friendship is also a theme, although it might be a bit of a stretch considering Godzilla's nature. But some fanfictions try to show how the ponies' friendship could influence Godzilla. And there's the theme of power. Godzilla has his own kind of power, and the ponies have their magic, and fanfictions often play with how these powers interact.
In a fanfiction, there could be a story where a pony discovers a magical artifact that can control Godzilla. At first, the pony uses it for fun, making Godzilla do small things like create waterfalls with its tail. But then, an evil force tries to steal the artifact to use Godzilla for destruction. The ponies then have to protect the artifact and convince Godzilla to help them fight the evil.
Luna might be initially cautious around Godzilla. Given her role as a princess in Equestria, she would likely try to assess if Godzilla is a threat. Godzilla, on the other hand, might be confused by the new environment. Eventually, Luna could use her magic to communicate with Godzilla, perhaps on a telepathic level. They would then start to understand each other's motives and find common ground, like protecting their respective homes from danger.
One possible plot could be that Godzilla somehow gets transported to the world of My Little Pony. The ponies are initially terrified, but then they realize Godzilla is there because he's being chased by an even greater threat from his own world. So, the ponies, with their magic, decide to help Godzilla fight off this threat and in the process, they learn about each other's strengths and form an unlikely friendship.
Sure. One interesting fanfiction could be 'When Godzilla Meets the Ponies'. In this story, Godzilla somehow ends up in Equestria and has to deal with the colorful ponies. There are also fanfictions that explore the idea of the ponies helping Godzilla when he's injured. Another good one might be 'Godzilla's Adventure in Ponyville' which shows how the different personalities of the ponies interact with the big monster.
One idea could be that Godzilla accidentally stumbles into Equestria. The ponies are initially terrified but then realize Godzilla is not there to harm them. They try to communicate and find a way to send him back to his own world.
A plot could involve a group of villains from another world who want to capture both Godzilla and Luna to use their powers. They manage to transport Godzilla to Equestria. Luna, being the protector of the night, finds Godzilla and realizes that they need to escape and fight back. Along the way, they meet various other My Little Pony characters who help them in different ways. Eventually, they face the villains and with their combined strength and the help of their new friends, they defeat the villains and Godzilla returns to his own world, but not before a new friendship is formed between him and Luna.
The interaction could be really complex. The ponies, being magical creatures, could try to use their spells to understand Godzilla's language or intentions. Godzilla, who is used to a world of destruction and chaos, might be confused by the colorful and peaceful world of Equestria. There could be a lot of misunderstandings at first. For example, when Godzilla roars, the ponies might think he's angry, but he could just be trying to communicate. And as they slowly start to understand each other, they could form an unlikely alliance. Maybe the ponies help Godzilla find his way home, and in return, Godzilla protects them from any future threats that might come from his world.
Well, you could start with the colors. Godzilla is often associated with dark, earthy tones like gray and green. In My Little Pony, there are bright and pastel colors. You could have a scene where Godzilla is in the My Little Pony world and his presence creates a contrast, like a dark shadow against the colorful meadows. The ponies' cute and small structures could be compared to Godzilla's massive size, creating an interesting aesthetic blend.
Definitely Godzilla and Twilight Sparkle. Godzilla is this huge, powerful force of nature, while Twilight Sparkle is a very intelligent and magically gifted pony. Their encounter would be full of contrasts. Twilight would be trying to figure out Godzilla using her knowledge and magic, and Godzilla would be this unknown entity to her. It would be interesting to see how they interact, with Twilight probably trying to communicate and Godzilla being more of a primal force at first.