One interesting idea could be the fusion of Naruto's ninja world with the Planet Hulk concept. Maybe Naruto characters having to deal with the harsh environment of Planet Hulk. For example, Sasuke might find new and powerful opponents there that force him to adapt his Sharingan abilities in unique ways.
A really cool concept could be that Naruto has to learn how to control the Hulk - like rage within himself. He discovers a new form that is similar to the Hulk's transformation, but it's powered by his own chakra. And the Hulk, in turn, could learn some ninja techniques from Naruto, like how to use stealth instead of just brute force all the time.
One idea could be that Naruto gains the powers of Captain Planet. He could use the power of Earth to create new jutsu related to the ground, like summoning huge boulders in a more eco - friendly way. Another could be a crossover where the villains in Naruto's world are causing environmental damage, and Captain Planet and his team come to help Naruto and his friends stop them. They'd combine their skills, with Naruto's ninja techniques and Captain Planet's elemental powers.
You could write about a group of Naruto characters traveling to a mysterious 'planet naruto fanfic' and having to adapt to its strange environment. They might encounter new enemies and form unexpected alliances with the locals there.
There could be a crossover where the Hulk's gamma - irradiated body has an unexpected reaction to the chakra in the Naruto world. Maybe his gamma energy mixes with chakra in a way that gives him new abilities or changes his appearance. This could lead to a whole new dynamic in the story, with both the Hulk and Naruto having to adapt to these changes while dealing with whatever threats come their way.
One idea could be a crossover where Naruto characters end up on the Cat Planet. They could learn about the unique cat - like cultures and powers there. Maybe Naruto tries to teach the cat people his ninja way, while also learning their feline - based fighting styles.
One idea could be exploring She - Hulk's life outside of her superhero duties. Maybe she has a secret hobby like painting that she uses to unwind. Another could be a story where she teams up with a lesser - known superhero and they learn from each other. For example, teaming up with a hero who has the power of invisibility but lacks confidence. They could go on a mission together and She - Hulk could help boost the other hero's self - esteem while also learning some new stealth techniques from them.
A plot could revolve around a scientific experiment gone wrong that affects only them. They start to lose control of their powers in different ways. Hulk might become too calm and lose his rage - fueled strength, while She - Hulk might turn into her human form at the wrong times. They have to work together to reverse the effects of the experiment, all while dealing with the problems that come with their power - changing states.
One idea could be that they team up to face a new super - villain who is immune to normal Hulk - like strength. So, they have to combine their smarts and unique Hulk - related abilities in a new way. Another could be a story where they explore their family connection in a more in - depth way, like dealing with the implications of being related Hulks in a world that still doesn't fully understand them.
Naruto could be the main character. He has the spirit and determination to adapt to the new and dangerous world of Planet Hulk. His ability to make friends and his never - give - up attitude would make him a great fit to be the central figure in this fanfiction.
One idea could be that the Hulk somehow gets transported to the DC universe. Maybe due to a freak accident involving some sort of interdimensional portal created by Lex Luthor in an attempt to bring in a powerful being to defeat Superman. The Hulk then starts rampaging through Metropolis, and Superman has to figure out how to stop him without causing too much destruction himself. He tries to reason with the Hulk at first, but when that doesn't work, he has to use his strength and speed to keep the Hulk occupied until they can find a way to send him back to his own universe.