Perhaps there's a glitch in Baymax's system that causes him to project Riley's emotions as holograms. Hiro is confused at first but then realizes that these emotions are from someone else. They track the source of the connection and end up in Riley's mind. There, they find that the emotions are in chaos because of the sudden link to Baymax. The Big Hero 6 characters use their skills to help the Inside Out characters restore order. Hiro and Baymax help Joy understand how to better manage the positive emotions while the rest of the team helps the other emotions like Sadness not feel so left out or misunderstood.
In a 'Big Hero 6' and 'Inside Out' crossover fanfiction, perhaps Riley visits San Fransokyo. During her visit, she witnesses an accident that Big Hero 6 is responding to. The chaos and destruction make Sadness start to surface strongly in her. Baymax senses her distress and tries to help her. This leads to the team inviting Riley to their lab to cheer her up. Inside their lab, the emotions are fascinated by all the high - tech gadgets and start interacting with them, causing some comical and unexpected situations as they blend the two very different worlds of technology and emotions.
One possible plot could be that the Big Hero 6 team is working on a new project in San Fransokyo when a strange series of crimes start to occur. These crimes seem to involve some sort of advanced technology that is out of this world. Spider - Man, who is on a school trip to San Fransokyo, senses that something is wrong. He starts to investigate on his own. Eventually, he crosses paths with the Big Hero 6. At first, there's some misunderstanding and a bit of a scuffle as they don't know each other. But when they realize they are after the same bad guys, they team up. Hiro figures out a way to integrate some of Spider - Man's web - slinging tech into Baymax's systems for a new attack mode, and together they take on the villain who is trying to use the stolen tech to create a portal to another dimension.
A plot might involve a villain who has stolen some of Syndrome's old tech and is using it in combination with the technology from Big Hero 6's universe. The Incredibles and Big Hero 6 team up to track down this villain. Frozone could use his ice powers to freeze some of the overheating tech created by the combined bad - guy tech. Honey Lemon's chemical - based gadgets could be used to counteract some of the effects of Syndrome's old inventions. And Jack - Jack, with his multiple powers, could provide some unexpected solutions and comedic relief during their adventure.
A great plot could be that there is a threat that is causing chaos in both the Naruto world and the Big Hero 6 world simultaneously. The two groups meet while investigating the source of this threat. Naruto, with his determination and strong will, would inspire Hiro to be more confident in himself. They could combine their unique abilities. For example, Naruto could use his shadow clone jutsu to help Big Hero 6 in a large - scale battle, while the technology of Big Hero 6, like Fred's suit, could be used to give Naruto an edge against certain enemies in his own world.
The interaction between the characters would be full of surprises. Consider Baymax and Joy. Baymax is all about helping and healing, and Joy is about spreading positive feelings. They could team up to make people in San Fransokyo feel better, Baymax by providing physical care and Joy by influencing their emotions. Then there's Hiro and Anger. Hiro might initially be annoyed by Anger's brashness, but over time, he could learn to use that energy in his battles. The other characters like Fred and the other emotions would also have their own unique interactions. Fred might try to show off to the emotions with his monster knowledge, and the emotions would either be impressed or find it a bit silly depending on their nature.
Hiro would likely be very curious about the emotions. He would try to study them and understand how they work. Baymax, on the other hand, would probably be very gentle and try to comfort any of the emotions that seem distressed, like Sadness. Go Go might be a bit impatient with the more timid emotions like Fear, but she would also respect their role. Fred would probably be excited to meet these new 'creatures' and want to be friends with all of them immediately. Wasabi would be a bit cautious at first, but then warm up to them.
One possible plot could be that the Big Hero 6 team visits San Fransokyo. There, they accidentally cross paths with the Incredibles who are on a secret mission. Hiro and Baymax are intrigued by the super - powered family. The two groups end up having to team up to stop a new villain who is using a combination of high - tech gadgets (like those from Big Hero 6's world) and superpowers (like those in The Incredibles' world).
It could be really exciting. Maybe the Avengers could visit San Fransokyo and be amazed by the high - tech there. Hiro could show them Baymax and they might collaborate to fight a new super - villain that threatens both their worlds.
One possible plot could be that the Big Three - Mirio, Nejire, and Tamaki - are transported to an alternate universe where they have to team up with their counterparts from different versions of BNHA. They face new villains and challenges that require them to combine their unique quirks in unexpected ways. For example, they might encounter a villain who can manipulate time, and they have to figure out how to use Mirio's intangibility, Nejire's wave motion, and Tamaki's transformation quirks to stop the villain before he destroys the fabric of the universes.
A cool Big Hero 6 crossover fanfiction idea might involve crossing over with the DC Universe. Hiro could meet Batman and learn about his detective skills and use of gadgets. Baymax could interact with Superman, which would be an interesting contrast of a big, strong hero and a soft, caring robot. Or perhaps a crossover with the Powerpuff Girls. The girls' superpowers combined with the tech - savvy of Big Hero 6 could lead to some really fun and action - packed adventures.