Well, Sonic might use his super speed in new and creative ways to outwit Eggman. Maybe he'll discover a new power - up.
Perhaps Sonic will face some moral dilemmas while trying to beat Eggman. He might have to choose between saving a group of innocent bystanders or going straight for Eggman's main control room. This would add more depth to his character. Also, Eggman could have some new and devious traps waiting for Sonic. But Sonic, being Sonic, will surely find a way to overcome them all.
There could also be some new characters introduced in this fanfiction. Maybe a mysterious figure who has some inside knowledge about Eggman's operations. This new character could either help Sonic or cause some trouble depending on their motives. Another possibility is a group of creatures native to the area where the battle takes place. They could be initially scared of Sonic and his friends but then end up helping them in some way.
In this kind of fanfiction, Sonic might be locked in one of Eggman's elaborate traps. Eggman could be planning to use Sonic's speed for his own evil experiments or to finally defeat him once and for all. Sonic would surely try to escape using his wits and speed.
A common theme is the power struggle. Eggman is always trying to gain power over Sonic's world, and Sonic is there to stop him. Another theme is redemption. Sometimes fanfics explore the idea of Eggman having a change of heart.
A plot could involve Eggman creating a device that accidentally swaps their minds. Sonic now has to figure out how to use Eggman's technology to reverse the process while in Eggman's body, and Eggman, in Sonic's body, is forced to experience what it's like to be the hero for a while. This would lead to some comical and also thought - provoking situations as they both learn about the other's perspective.
Well, in a typical scenario, Sonic would probably rush to save Tails. He'd use his super speed to track Eggman's lair. Maybe he'd find some clues along the way, like a piece of Tails' fur or a gadget that Eggman accidentally dropped. Then, Sonic would face off against Eggman's badniks, defeat them one by one, and finally reach Tails. He'd free Tails and they'd escape together, with Eggman vowing revenge as usual.
The dynamic between Sonic and Eggman. They are arch - enemies, so seeing how they interact in fanfics, whether it's in a battle of wits or an unexpected team - up, is always exciting.
First, understand the characters well. Eggman is a brilliant but egotistical villain, and Sonic is a heroic and speedy hedgehog. Keep their personalities consistent. For example, Eggman would always be scheming and Sonic would always be ready to save the day. Also, create an interesting plot that involves their relationship, like a battle of wits or an unexpected alliance.
Tails would be the first one to come to Sonic's aid. His intelligence and flying ability would be very useful in finding Sonic and getting past Eggman's defenses.
Well, one possibility could be that Sonic and Eggman are forced to team up against Black Doom. Maybe Black Doom is threatening to destroy their world, and they realize that only by combining their strengths, Sonic's speed and Eggman's technology, can they stand a chance.
A really cool Sonic and Eggman fanfiction could be set in an alternate universe. In this universe, Sonic is not the hero he is in the main canon. Instead, he's more of an anti - hero, and Eggman is the one trying to save the world from Sonic's reckless behavior. It flips the traditional roles and makes for a very engaging read.