It could be that there's a prophecy in their world that says one of them will cause great destruction. Some of the other characters start to suspect Tails because of his intelligence and the things he can create. Sonic, influenced by the rumors, challenges Tails. Tails, feeling betrayed, fights back. In the end, they discover that the prophecy was misinterpreted and they reconcile.
One possible plot could be that there is a powerful new item in their world. Sonic thinks it should be used immediately to stop Dr. Eggman, but Tails believes they need to study it more first. This disagreement leads to a fight as Sonic tries to take the item by force and Tails tries to stop him.
One possible reason could be a misunderstanding. Maybe Sonic accidentally broke something of Tails' while on a high - speed chase. Tails, being a bit sensitive about his inventions, might get angry and start a fight.
The fight could end with Sonic realizing he was wrong. If it was a misunderstanding, Sonic's quick thinking and good heart would make him apologize to Tails, and they would make up.
One possible plot could be that Sonic yells at Tails because Tails made a risky decision during a mission that almost put them both in danger. For example, Tails might have tried to take on a powerful enemy alone without waiting for Sonic's backup.
I haven't actually read this specific 'sonic and tails fight fanfiction' yet. But generally, in Sonic fanfictions, the fights between characters can be really exciting. They often show off different abilities of Sonic and Tails. Maybe in this one, it could be about a misunderstanding that leads to their fight, like one thinking the other has been influenced by some evil force.
In a 'dark sonic vs tails' fanfiction, perhaps Dark Sonic is corrupted by some dark energy. Tails, being the intelligent fox, tries to use his gadgets to fight back. Dark Sonic might have super - speed and enhanced strength due to the dark influence. Tails could be outmatched at first but then uses his wits to find a weakness in Dark Sonic's dark - powered state. Maybe he discovers a frequency that disrupts the dark energy, leading to a final showdown where Tails has to time his attack just right to save Sonic from the dark side.
Well, it could be that Sonic is dashing through the forest on one of his adventures when he suddenly hears a strange noise. He follows it and discovers Tails, who is trying to fix his broken plane. Sonic is immediately intrigued by Tails' two tails and his mechanical skills.
Well, perhaps in the fanfiction, Tails' nightmare is about his inventions going haywire. He dreams that all his machines turn against him and Sonic, and they have to fight their way through a mechanical nightmare. This might show his underlying worry about his creations causing harm rather than good.
In this fanfiction, perhaps Sonic Underground is facing a threat that they can't handle alone. Tails, being a friend of Sonic from another part of their world, comes to their aid. They discover that an ancient evil has been awakened. The story could involve Tails using his inventions to analyze the ancient evil's weaknesses while Sonic and his siblings use their unique abilities to keep the evil at bay. As they progress, they form a strong bond and learn from each other's ways of doing things.
Another plotline could involve their relationships. Sonic, as the younger one, might be more naive in some ways and look up to Tails for guidance. Tails, in Sonic's body, could find it strange to be the center of attention and the one expected to lead. Their friendship dynamic would change completely. Maybe Sonic would start to envy Tails' natural intelligence more, while Tails would realize how much pressure Sonic was under all the time.
It's not a common plot. Fanfiction writers often prefer to write about more traditional Sonic - related themes such as Sonic's heroics, the exploration of new zones, or the development of character relationships. 'Tails saves sonic fanfiction' is a rather specific and less - explored concept. However, with the wide range of creativity in the Sonic fanfiction community, it could potentially gain more popularity in the future.