Well, you might start by exploring how the switch affects their relationships with other characters. Also, think about how they adapt to each other's skills and limitations. That could make for an interesting story arc.
You could have them try to find a way back to their original bodies while facing challenges that test their newfound abilities. Maybe there's a magical element involved in the switch that needs to be undone. It all depends on the tone and direction you want the fanfiction to take.
One way could be to focus on the confusion and adjustments the characters have to make. It can add a lot of drama and humor.
You could have other characters come to his rescue and help him recover.
This is a tricky one. Maybe the other characters could come to Hiccup's aid and help him break free. Or it could be a journey of self-discovery for Hiccup while in that situation.
I think you could focus on Hiccup's growth and transformation after the betrayal. Maybe he becomes stronger or learns valuable lessons. Also, you could have him seek revenge or find a way to forgive and reconcile.
First, you should try to understand the underlying emotions causing Hiccup to do that. Maybe he's going through a tough time or facing some internal conflicts. Then, you could explore ways for him to find healthier coping mechanisms, like talking to friends or seeking help from a mentor.
First, you could have the other characters in the story come up with a rescue plan. They might use their skills and knowledge to track down where Hiccup is being held and figure out how to get in safely.
You could focus on showing his gradual change through significant events or interactions with other characters.
One way is to introduce a special cure or remedy that Hiccup discovers during his adventures. You can also explore how his friends and allies support him through this difficult time.
One way could be for Hiccup to seek the help of other dragon riders or wise elders who might have knowledge about breaking the curse.
First off, you might introduce a wise healer character who knows the remedy. Or, you could have Hiccup's friends embark on a dangerous quest to find the cure. Another option is to have Hiccup's inner strength and determination help him fight off the poison gradually.
One way could be having his friends rally around to care for him and look for a cure.