Fanfictions about watching HTTYD 3 in the past often focus more on the viewer's personal experience and how the movie affected them. Normal HTTYD 3 fanfictions usually center around the events and characters within the movie's universe directly.
Well, they might be shocked at how much technology has advanced in the future depicted in the fanfiction. Maybe there are new types of elemental powers or different ways of training ninjas. It could also be that the relationships between characters have changed in unexpected ways, and they would have to come to terms with that.
They might gain a new perspective on their own abilities. If the future fanfiction shows ninjas with enhanced powers, the past characters could start to think about how they could develop their skills further. For example, if in the future they can combine elemental powers in new ways, the past ninjas might start experimenting.
One of the best things is seeing the characters' growth. In fanfiction, it might explore Hiccup's further development as a leader. For example, how he deals with new challenges in Berk. Also, the relationships between the characters can be delved deeper. Toothless and Hiccup's bond might be shown in more emotional and complex ways, like their adventures in new, uncharted lands.
It extends the story. After the movie ends, fanfiction can continue the adventures. Maybe Hiccup and his friends go on a new quest that was only hinted at in the movie. It gives fans a chance to keep exploring the world they love and see what could happen next.
Toothless is another great candidate. As Hiccup's dragon, he has a unique bond with his rider. In a past - meets - future story, he could be the one to sense the disruptions in time. He might also meet his descendants or ancestors in the future or past dragons, which could lead to some really interesting interactions. For example, an ancient dragon from the past might teach Toothless a long - lost skill that helps them in a future battle.
Yes, there are likely some popular ones. For instance, some fanfictions that explore the relationship between Hiccup and Astrid during the time leading up to HTTYD 2 are quite popular. They might show how their relationship evolves and how they support each other in anticipation of the new threats in the second movie.
One idea could be that an old enemy from the past resurfaces in the future, but with new and more powerful abilities. The dragons and riders have to combine their old - school knowledge with the new technology they've developed over time to defeat it.
The characters would face the challenge of not being recognized or being seen as a threat. If they time - travel to a time when their families or tribes didn't know them yet, they could be considered outsiders. For example, Hiccup might be seen as a strange boy with his un - Viking - like ways of handling dragons. Also, they would have to deal with the different cultural norms of the past. Things like how battles are fought, how the tribe is led, and how resources are shared could all be very different, and they would need to adapt quickly to avoid getting into trouble.
Well, in the real world, it's not possible. But if we were to think in a more creative, fictional sense, like in a meta - story where the httyd world intersects with our own digital or written realm in some magical way, then maybe. But generally, no, as it's just a fictional entity without the physical or mental faculties to do such a thing.