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.
In a Pokemon fanfic when Pikachu gets sick, it might become very weak and unable to battle. Ash would probably be really worried and take it to a Pokemon Center right away. The Nurse Joy there would use her skills and Pokemon medicine to try and heal Pikachu.
In 'naruto and pikachu fanfic', often we see a cultural exchange of sorts. Naruto's values as a ninja, like loyalty, hard work, and protecting his friends, can be contrasted and combined with Pikachu's more innocent and friendly nature. This can lead to some heart - warming moments in the fanfic. For example, Pikachu might help Naruto understand the importance of having fun in the middle of all the serious ninja business. And Naruto could teach Pikachu about the importance of training and discipline. Also, the power combinations are really cool. Naruto's ability to use chakra and Pikachu's electric attacks can be merged in unique ways, like Naruto using his chakra to enhance Pikachu's electric blasts for a super - powerful attack.
It could be a new character, a powerful dark wizard who wants to use the combined power of Naruto's chakra and Pikachu's electricity for his own evil purposes. He creates all sorts of dark creatures and sends them after Naruto and Pikachu to try and capture them. He's very cunning and has a lot of minions to do his bidding.
Well, Naruto's chakra-based powers and Pikachu's electric powers can combine in some fanfictions. For instance, Naruto could use his Rasengan and Pikachu could add its electric charge to it, creating a super - charged attack that is more powerful than either of their individual attacks.
Ash would be extremely worried. He'd do everything he could to make Pikachu feel better, like staying up all night to take care of it. Misty might offer some practical advice, like making sure Pikachu stays warm. Brock would probably be ready to cook some special food for Pikachu to help it regain its strength.
The plot could be that Naruto discovers Pikachu in the Hidden Leaf Village. Maybe it was lost from the Pokémon world. Naruto, being the kind-hearted ninja he is, decides to take care of Pikachu. They then go on adventures together in the Naruto universe, with Pikachu using its electric attacks to help Naruto in battles against the bad guys.
A possible fanfic could be where Pikachu gains the ability to use Naruto's ninjutsu. So, Pikachu starts using Rasengan and other cool ninja moves. And Naruto teaches Pikachu how to be a better fighter in his own way. They then enter a big tournament in the Pokemon world together and show everyone their unique combination of skills.
Well, it could be about Naruto finding a strange, electric - type creature in the Hidden Leaf Village and discovers it's a female Pikachu. They might start off as curious about each other. Maybe Pikachu uses her electric powers to help Naruto in a fight against some rogue ninjas. And as time goes on, they form a bond that is unique to their cross - world friendship.
There's also a fanfic where Naruto somehow gets transported to the Pokémon world and befriends Pikachu. In this story, Naruto uses his ninja skills along with Pikachu's electric powers to fight against some evil Pokémon trainers who are misusing their Pokémon. It's really interesting to see how the two different power systems interact.