An early ancestor of Clan McDuck, Bubba was attempting to retrieve a golden artifact when Louie and Launchpad arrived from the future. Bubba was zapped with the energies of Gyro Gearloose's Time Tub, which caused him to be brought to present day McDuck Manor.
He soon befriended Dewey and Webby, while Huey was baffled by Bubba's defiance of his expectations regarding cave ducks. Bubba helped the residents of the manor deal with various other time-displaced beings, before being returned to his own time, bringing back with him the club of the first-known ancestor of Clan McDuck — paradoxically indicating that he was that caveduck, as further confirmed when, inspired by the sight Scrooge McDuck's top hat, he carved himself a piece of stone headgear resembling one, completing the image.
Behind the scenes
Bubba McDubba was introduced in the DuckTales 2017 episode "Timephoon." Though mostly an updated version of Bubba the Cave Duck from the original DuckTales, his advanced skills and implied connection to Clan McDuck resemble the comics character Muk-duk. He was also alluded to in the comic story Countdown to Termination.