After encountering General White at the top floor of Muscle Tower, the sneaky Red Ribbon Army leader sent Goku and Hachan falling (via dastardly trap door) into the hidden room below! White makes Goku a last offer - hand over his Dragon Ball and Dragon Radar, and he'll spare his life. Goku rejects his offer fervently. So White closes the trap door, and summons the guardian of the 5th floor... He's pink, he's round, has antenna, and he'll eat you...
Close, but not yet, Buu.
I am, of course, referring to ...
Hachan is frightened, and General White cackles over his radio, taunting Goku and commanding Buyon to eat him. But Goku knows he can't lose!! Despite Goku's best punch (which he claimed would take Buyon out in one hit!), Buyon's pudgy body simply absorbs the damage! "No way! My punches have no effect at all! Alright, in that case... Try a kick!"
White chortles over the radio, saying that Buyon is invincible. Goku is inclined to agree, but lunges at Buyon to give it one more try...!
So Buyon shocks the shit out of him.
...Then eats him.
At this point, things look over for our hero. But Goku teaches Buyon a lesson about chewing your food properly.
Buyon sends a rapid fire assault of electricity at Goku, who dodges each of them... but grows concerned that all he can do is run away. Hachan notes that Goku looks exhausted, and Goku says he's hungry too... then an idea dawns on him! The Kamehameha!
Which does little more than make Buyon's belly jiggle.
White offers Goku one last chance of surrender, which Goku shouts down immediately. But while distracted with White, Buyon's tongue lashes out and scoops up Hachan!! Goku leaps at them in intervention, kicking Hachan out of Buyon's tongue at the last moment - but Hachan's brush with death has made up his mind... "We are done for, Son Goku. There is nothing we can do..." Hachan says dejected. "Don't talk so pathetically, Hachan! Men can't give up!" ...But privately, Goku agrees.
If only Buyon's body were solid...
"Frozen? What's that?"
"It's where you're so cold you turn hard like ice."
So Goku breaks open Muscle Tower's wall, letting in the blizzard.
Hops into Hachan's coat (Hachan is immune to weather, natch.)
Waits for Buyon to freeze...
And Goku is 3 and 0, in the battle for Muscle Tower.
Goku uses his head, leaping high into the air and busting through the ceiling of the 5th floor - landing back in White's office! He extends his Nyoibo for Hachan, and uses it to bring him up as well. White, seeing an opening, takes out his gun and shoots Goku several times in the back...!!
But the bullets don't do shit. Looks like White done fucked up now.