The Hikui Bird one of the few Dragon Ball anime filler characters known to have been designed by Akira Toriyama himself. Physically, Hikui Birds look like huge ostriches, even though they can fly while ostriches are flightless birds. They also look a lot like the cassowary, another flightless bird that, just like the Hikui Bird, has a large bony projection on top of its head.
The Hikui Bird is a rare and near extinct bird that eats flames and dwells in Mount Kiwi's volcano. It was the subject of study of an old scientist for 40 years. The scientist traveled to Mount Kiwi, found the last egg of the Hikui Bird, and kept it until the day it hatched.
Goku and Chi-Chi find a book written by Master Roshi where he claims that Hikui Bird's feathers must be collected in order to create the legendary Bansho Fan, but he later admits that he only wrote that to impress the girls. Without knowing the truth, Goku and Chi-Chi go to Mount Kiwi searching for the bird's feathers to create a Bansho Fan and put out the flames at Fire Mountain in order to save the Ox-King.
Emperor Pilaf also know about the Hikui Bird and go to Mount Kiwi intending to steal the egg and later sell it for a lot of money, but Goku stops Pilaf's evil plans and he, Shu and Mai have to run away once again.
When the last Hikui Bird alive appears, he breaks his own egg's shell to help the cub hatch. After that, both the adult and the cub stare at Goku, Chi-Chi and the old scientist for a few seconds (probably as their own way of thanking them for taking care of the egg) before leaving the volcano and disappearing in the sky. The adult Hikui Bird leaves some feathers behind, but they just disappear when Goku and Chi-Chi try to catch them.