( Please note I'll be making uub stronger than in the original as well as introducing a new concept for the character also no god ki and ultra instinct this is gt not super Though Goku is way stronger after 15 years of training and could fight against buuhan in just base and would probably dominate the fight easily like super Vegito vs buuhan )

'Rumble'

" I know the lookout was designed for stuff like this but the cracking floors starting to make me nervous," Dende says in a nervous tone.

'crack boom'

"Dende and Mr.popo watch has the lookout falls apart and the floors crack due to Uub's and Goku's fight".

" Mr.popo I think leaving here would be a safe option."

( Somewhere inside the lookout)

"Kamehameha,"  Goku and uub both yell the name of their attack in unison."

'rumble'

The earth below them begins to shakes as the beams of energy clash.

" You have become a lot stronger uub," Goku says this almost out of breath.

" I wouldn't be anywhere near as strong as I am today without you training me Goku."

" It's about time we end this fight then uub I haven't been home in years and chi-chi is probably going to kill me if I don't get back soon," Goku says, shivering at the thought of chi-chi's wrath

Uub lets out a wry laugh, has he responds to Goku's comment, "I guess even the strongest man in the universe has something that he's afraid of."

" Time to pick things up where we left off."

" hah!"

Letting out a loud shout Goku powers up to Super Saiyan and charges at uub delivering a voracious right hook causing uub to fly backward after impact.

'crash'

uub gets back up and wipes the blood from the corners of his lips and begins to fire multiple ki blasts at Goku.

Though Goku dodges them with ease and delivers another punch towards uub Causing him to fly into the pile of rubble behind him.

Uub stands up seemingly annoyed by not being able to lay a hand on super Saiyan Goku has steam starts to come off his body his sclera turn dark and his pupils turn a deep red and his aura becomes dark and disturbed.

" hahaha hahaha"

UUb lets out a sinister laugh seemingly losing control as his dark aura begins to spike. clenching his fist he punches himself in his face has his aura stops spiking.

" sorry Goku almost lost control there this form really is pretty hard to keep control of  "

Goku lets out a smirk thinking back to when uub first discovered this power and was unable to control it but after a few years of training, he's beginning to slowly master his new form.

( 10 minutes later )

" So how did uub do," Asks a Dende with a slightly ruffed up appearance.

" He passed with flying colors," Goku says in an exhausted tone. 

After uttering these words Goku falls to the floor.

"I'm so hungry."

" Mrs.popo gets the first aid kit and some food," Dende says in an alarmed tone.

( 2 hours later )

" you have any more of this," Goku asks While scarfing down is the 30th serving of food.

" he wants more."

Goku was about to move on to his 31th serving when he heard a large rumble and the sky turned dark.

giving Dende a Questioning look Goku asks Dende if anyone had gathered the dragon balls in the past few days.

" no not to my knowledge"

getting even more curious after Dende's reply Goku rushes outside of the lookout only to find a group of familiar-looking people and a giant red looking Shenron

" You look familiar but I can't place it," Goku says in deep thought.

"Pilaf-sama doesn't that guy look like that Goku kid that's always ruining our plans,"  Shu asked pilaf seeming a little worried

"yea expects now he's all grown up and has a body that looks like it was carved out of marble," Mai replies.

"  Now I remember your emperor pilaf."

" no, I'm not."

" Nope, I sure you are I'd have a hard time forgetting blue skin and pointy ears."

Panicking pilaf orders Mai to fire missiles at Goku but to his dismay Goku makes a finger gun shooting small ki blasts at the missiles destroying them.

Seeing this pilaf couldn't help but remember how Goku ruined all his plans.

"I hate you son Goku I hope you die and get plunged into the deepest depths of hell,"  Pilaf shouts angrily.

" Your wish shall be granted,"

Making this Statement Shenron disappears and the black star dragon balls split across the universe has Goku's lifeless body crashes to the ground.