Yes, in the vast world of fanfiction, there are all kinds of creative and out - of - the - box stories. Some fans like to explore unusual relationships and scenarios, so it's possible that there is such a fanfiction out there. However, it goes against the original canon of the Dragon Ball series in many ways.
It could be Vegeta. Maybe Vegeta does something really underhanded like stealing Goku's senzu beans or trying to take all the credit for a victory that Goku also contributed to. Goku, being a fair - minded person, would get angry at such behavior.
His anger often manifests physically. His muscles might bulge more than usual, and his hair could stand on end even more in his Super Saiyan forms. His ki, or energy, also becomes more visible and intense. It's like a red - hot aura surrounding him.
Goku might adapt slowly at first. He's used to his own way of life on Earth and in the Dragon Ball universe. But his determination would help. He would learn the rules and schedules just like he learned new fighting techniques.
There may be such fanfics in the vast world of fan - created content, but it often goes against the original storyline's intended relationships in the Dragon Ball series. In the official story, Goku is married to Chi - Chi, not Bulma.
It could be a new, self - created villain. This villain might have been training in secret for years, specifically to defeat Goku. He could have studied all of Goku's moves and weaknesses and then launch a surprise attack that causes Goku to get hurt.
It could be a female Namekian. Since Namekians are also very strong and have their own unique culture, a female Namekian could catch Goku's eye. They might bond over their mutual respect for life and their experiences with fighting powerful foes.
In such a fanfiction, Goku might be kidnapped by a powerful new villain. His friends would then start a search mission. Maybe Vegeta would be the first to volunteer, thinking it's his chance to prove he's stronger than Goku.
One common theme is rivalry. Goku might get jealous due to a rivalry with another character, like Vegeta. Another theme is family. His jealousy can be related to his family members, such as when he feels left out or less important.