Sir Hubris is a mythical character from an ancient Gorg legend that tells of the beginning and end of the Gorg dynasty.
According the the legend, before time began, the Universe was ruled by a mysterious creature named Sir Hubris. Sir Hubris was not a Gorg; in fact "he was only half the height of a Gorg and not even a hand width in girth." The short and skinny Sir Hubris was unhappy, for he wished to see and explore his realm, so one day he put on his brown, hooded traveling cloak and set off to wander through the Universe. But before leaving, Sir Hubris gave his crown to King Gorgus the Great, the first Gorg king. Since then, the Gorgs have ruled the Universe. However, if Sir Hubris ever returns, the crown must be turned over to him and the reign of the Gorgs will be over. The Gorgs would pack their things and be forced to wander the Universe, indicating that there is more to the Universe than shown.
Ma Gorg reads the legend of Sir Hubris to Junior in the Fraggle Rock episode "Sir Hubris and the Gorgs." However, Gobo overhears the tale and decides to trick in the Gorgs into leaving forever by having the Fraggles pretend to be the cloaked Sir Hubris.
Junior Gorg owns a copy of The Adventures of Sir Hubris, as seen in "The Great Radish Caper."