The King of the Golden River is a magically powerful gnome of disputed existence.
The King of the Golden River is, according to the eponymous fairy story, a powerful gnome who rules over the Golden River, rewarding the unselfish by allowing them access to the River's titular golden boon. In 1958, Huey, Dewey and Louie Duck and their uncle Donald impersonated the King, believing him to be fictitious, to teach Scrooge McDuck a lesson about selfishness, having figured that the "trick" to controlling the flow of gold was nothing magical, but simply a matter of whether or not some hot springs were connected to the main riverbed. However, in the course of this adventure, one account states that one of the children briefly caught a glimpse of a gnome identical to the way Scrooge had imagined the King…
Behind the scenes
As a fiction, the King of the Golden River is mentioned in the 1958 Carl Barks story Uncle Scrooge and the Golden River. The story remains ambiguous over whether the gnome really existed, but a 2009 illustration by Don Rosa seems to confirm that he did.
He is, of course, based on the character of the same name in John Ruskin's The King of the Golden River. The original story goes into more detail about him than his relayed in the story: Gluck's act of selflessness is to help free the King from a golden mug in which he had been magically trapped by "a stronger King". He is described by Ruskin not as a gnome but as a dwarf in Ruskin's text; illustrations for the story usually depict him as more gnome-sized than dwarf-sized, but do give him a beard.