The plot could be about a baby boy who is just learning to crawl while wearing his diaper and onesie. His adventures might include trying to reach a favorite toy across the room or exploring the textures of different things in his diaper and onesie.
The boy in the diaper and onesie would be the central figure. There could also be a pet in the story, like a dog or a cat, that is curious about the boy's diaper and onesie. The pet could be another important character, adding some fun and chaos to the story as it tries to play with the boy's diaper or chew on the onesie.
The change in its appearance can make it scary. For example, if its usually cute yellow fur turns dark or if its bright red cheeks become a sinister red glow. Also, if it starts to behave in an uncharacteristic way, like making menacing noises instead of its usual cute sounds.
Obviously, the main characters are usually Pikachu. But sometimes, there could be other Pokémon that play important supporting roles. For instance, a Pichu could be a sidekick or a younger Pokémon that the Pikachus are protecting.
One interesting plot could be two Pikachus from different regions meeting and learning about each other's unique electric attacks. For example, one Pikachu might know a special move that the other has never seen before. They could then teach each other and become stronger together.
Naruto would probably be really excited. He'd treat Pikachu like a new friend and teammate. He might try to learn all about Pikachu's powers and how it can help in battles. For example, he'd be eager to see Pikachu use Thunderbolt in a fight against an enemy ninja.
Lucario is also a popular choice to be paired with Pikachu in crossovers. Lucario has its own unique abilities related to sensing and combat. When combined with Pikachu's electric attacks, they can form a formidable team. The contrast between Lucario's more serious and stoic nature and Pikachu's cute and energetic personality also adds depth to the story.