Their fused form might have Goku's spiky hair, but with some of Goku Black's purple - tinted highlights. The body would be muscular like Goku's, but with a more menacing stance similar to Goku Black. The clothing could be a combination of Goku's orange gi and Goku Black's black under - shirt, maybe with some red accents added in for an extra pop of color.
In fanfiction, if Goku Black fused with Goku, it could potentially create an extremely powerful being. This new entity might have a mix of Goku's pure heart and Goku Black's more sinister motives, which could lead to a complex internal struggle. Their combined power could be off the charts, perhaps strong enough to defeat any foe in the Dragon Ball universe. However, it could also cause chaos as their different personalities clash within the fused form.
The plot could involve Goku and Goku Black fusing accidentally. Maybe due to some strange energy anomaly. And then they have to figure out how to control this new form. They might initially be feared by their friends because of Goku Black's reputation, but then they prove that they are on the side of good by using their new powers to protect the Earth from an impending threat that no one else could handle.
Well, I've come across a few. Some explore Goku Black's relationship with Goten in really unique ways. For example, there are stories where Goku Black has a change of heart due to his interactions with Goten. It's really fascinating to see how different authors play with their characters' personalities and the overall Dragon Ball universe in these fanfictions.
It could be Zamasu. Since Goku Black was Zamasu in Goku's body in the original story, perhaps a more powerful and enraged Zamasu could be the main antagonist. He might be jealous of the new fused form's power and seek to destroy it.
One common theme is redemption. Goku Black, being a villain, might find redemption through his connection with Goten. Another theme could be power dynamics, as Goten has his own set of powers and how they compare or interact with Goku Black's is interesting to explore.
There might be a fanfiction where Goten gets lost in time, and Goku has to travel through different eras to find him. Along the way, Goku meets versions of his friends from different time periods and has to team up with them to rescue Goten. This would involve a lot of action and emotional reunions.
In this fanfiction plot, a powerful sorcerer or some sort of interdimensional being could be the cause of the fusion. The fused Naruto - Goku would have an insane amount of power. They could travel at super - fast speeds like Goku and also use shadow clones like Naruto. Their power level would be off the charts. They might end up in different parts of the new world they're in, trying to find each other and figure out what happened, all while being chased by enemies who want to study or destroy their new form.
One great fanfiction is 'Goku and Goten's Training Days'. It focuses on Goku teaching Goten new techniques. It's really exciting as it shows their father - son bond through the training sessions.