Well, in some 'hiccup has a different dragon' fanfictions, the dragon might have special powers not seen in the original. For example, it could have the ability to control time on a small scale. This would change the way Hiccup interacts with it and the adventures they go on.
The main deviation is often the dragon itself. In the original, the dragons have certain characteristics, but in the fanfiction, the 'different dragon' might break those norms. For instance, if the original dragons are mostly fire - breathers, the new dragon could have ice - based powers.
There probably is. Fanfiction is a vast world, and given the popularity of Hiccup and dragon - related concepts, it's not a stretch to think that someone has written a fanfic about Hiccup having a Stardust Dragon. Check the relevant fandom sections on major fanfic platforms.
In some fanfiction, Hiccup might kill a dragon because it was corrupted by a dark force. He may have tried to save it first, but when all else failed, he had to end its life to protect others. This would show his growth as a character, from someone who once befriended a dragon to someone who has to make tough choices to safeguard his people and the world he lives in.
One common plotline is Hiccup's discovery of the dragon wings. It could be through some magical event or an accident. For example, in a popular fanfic, he touches an ancient relic and suddenly sprouts dragon wings.
Well, it might be that Hiccup gains wings through a powerful spell or a special encounter with a mythical creature. This could give him new abilities and challenges in the story.
This kind of fanfiction could show how the twin's presence changes Hiccup's journey. Maybe they have contrasting personalities that lead to interesting conflicts or collaborations.
In 'hiccup the dragon fanfiction', one aspect could be the different dragon species and their characteristics. Hiccup might interact with various dragons, not just Toothless. It could show how he learns to communicate and cooperate with different types of dragons. Also, it might include some emotional parts, such as the bond between Hiccup and his dragon when they are in difficult situations, like being separated or facing a life - threatening danger.