Batman in Catwoman's body would likely be very cautious at first. He's used to his own physical strength and abilities, and now he has to adjust to Catwoman's more agile and stealth - based skills. He might also struggle with the more flirty and carefree attitude that Catwoman often portrays. As for Catwoman in Batman's body, she would have to deal with the serious and brooding nature of Batman, which could be a big change from her own personality.
I think Iron Man and Hulk would be a really interesting pair. Just imagine Tony Stark's brilliant mind trapped in the Hulk's huge, rage - filled body. He would be constantly trying to find a way to control the Hulk's strength and not go on a rampage. And Hulk in Tony's body would be so confused by all the technology and might accidentally set off some of Stark's weapons.
There was a young man, Jack, who through a magical spell switched bodies with a girl, Emma. Jack, now in Emma's body, was astonished by the change. He realized that Emma had a very different daily routine. He had to attend ballet classes which he initially thought would be easy but turned out to be quite difficult. As he spent time in her body, he became more empathetic towards the female experience, like the pressure to look a certain way. Eventually, with the help of an old wizard, they switched back.
There could be a scientific experiment gone wrong. For example, they are in a lab for some school project on teleportation or something similar. But instead of teleporting, their minds or consciousness get transferred to each other's bodies. Another way could be through some kind of alien technology. An alien device that was meant for something else malfunctions and causes their bodies to switch.
Once upon a time, there was a girl named Lily and a boy named Tom. One day, they both touched a strange old mirror at the same time in an antique shop. Suddenly, they found themselves in each other's bodies. Lily, now in Tom's body, was shocked to see her new male appearance. She had to deal with Tom's football practice. Meanwhile, Tom in Lily's body had to attend ballet class. In the end, they worked together to find the same mirror again and reversed the situation.
I think there could be several such novelas. One example might be 'The Swap' where two girls magically switch bodies and have to navigate each other's lives.
One possible reason could be mind control. Maybe some villain has taken over Superman's mind and made him do it. Another reason might be a fundamental difference in their ideologies that has escalated to the point of no return.
Lois Lane is often a popular character. In fanfiction, she might play a crucial role in mediating between Batman and Superman or getting involved in their adventures in a more hands - on way, using her investigative journalism skills.
Alfred Pennyworth is quite popular too. He can offer his wisdom and support to Batman, and his interactions with Superman can be both humorous and heartwarming. He's like the glue that holds things together in the Batcave, and his presence can bring a sense of home to the story.
There would be some humorous moments too. Harry might not be used to wearing Ginny's clothes and would fumble with the different styles. Ginny, in Harry's body, might accidentally use his more masculine way of speaking and shock her friends. Also, if they had to participate in Quidditch in each other's bodies, it would be quite a sight. Harry, in Ginny's body, would have to adjust to her style of playing, and Ginny, in Harry's body, would have to live up to his reputation on the broom.