Most of the time, Rainbow Dash's pranks are in good fun. With ponies like Pinkie Pie, her pranks can strengthen their relationship. Pinkie Pie loves a good laugh and would probably find Rainbow Dash's pranks hilarious. They would bond over the shared humor and it would make their friendship even closer.
However, with ponies like Twilight Sparkle, who are more focused on studies and order, Rainbow Dash's pranks might initially cause some friction. For example, if Rainbow Dash pranks Twilight by scattering all her books around the library, Twilight might be annoyed at first. But over time, Twilight would come to understand that it's just Rainbow Dash's way of having fun and they would learn to tolerate and even enjoy each other's differences.
Maybe Rainbow Dash would play a prank on Fluttershy by hiding all of her little animal friends. She would do it in a harmless way, of course. She'd then pretend she has no idea where they are while Fluttershy starts to worry. Eventually, Rainbow Dash would bring them all back and have a good laugh with Fluttershy about it.
Twilight Sparkle would likely be devastated. She would probably try to use her magic to bring Rainbow Dash back, spending countless hours in her library researching any possible spells or solutions. Pinkie Pie, on the other hand, would initially be in denial. She would keep waiting for Rainbow Dash to show up at parties and do all the fun things they used to do together.
Sakura's reactions can vary. Sometimes she tries to get revenge on Naruto for his pranks. If he plays a prank that makes her look silly in front of Sasuke, like the fake love letter prank, she'll be really mad and try to think of a way to make Naruto pay. Sasuke might pretend not to care, but if the prank affects his image too much, like the hair product switch, he'll give Naruto a cold stare. Kakashi is more laid - back and just watches the whole thing unfold like it's entertainment.
In a fanfiction, Rainbow Dash's brother could be an outcast among the ponies. He doesn't have the same level of confidence as Rainbow Dash and struggles to find his place. However, through a series of adventures and with the help of Rainbow Dash and her friends, he learns to embrace his own strengths and differences, and eventually becomes a respected member of the pony community.
Another scenario in a fanfiction could be that Rainbow Dash contracts a mysterious illness that no pony can cure. As she gets weaker, the ponies around her try their best to help. But in the end, she succumbs to the illness. Her death would cause the ponies to come together to find ways to prevent such a tragedy from happening again, perhaps leading to new medical discoveries in Equestria.
One great fanfic could be about Rainbow Dash taking Scootaloo on a special flying adventure. It might include Rainbow Dash teaching Scootaloo new flying techniques. This would strengthen their bond and show how much Scootaloo looks up to Rainbow Dash.
Well, some start with the human already being a big fan of My Little Pony in their own world. Then, through some kind of wish - fulfilling magic or a dream that turns real, they find themselves face - to - face with Rainbow Dash. This initial encounter sets the stage for all the adventures and interactions that follow in the fanfiction.
Naruto could enlist the help of his friends like Shikamaru. Shikamaru could come up with a really elaborate plan. For example, they could set up a fake mission where Ibiki thinks he's in charge, but it's all just a setup for a series of pranks. They could have actors pretending to be enemy ninjas who act really silly instead of being threatening. And Naruto could keep popping up in unexpected places during this 'mission' to further annoy Ibiki.
He could be a prodigy in a different area than Rainbow Dash. For instance, while she is great at flying stunts, he could be a master at creating flying devices. The plot could revolve around him creating a new type of flying machine that gets stolen by an evil force in Equestria, and Rainbow Dash and her friends have to help him get it back.
One popular Rainbow Dash fanfiction is 'Flight School Days'. It focuses on Rainbow Dash's early days at flight school, her struggles and how she overcame them. Another is 'Rainbow Dash and the Great Race' where she participates in an epic race across Equestria.