The ancient continent of the Mesozoic serpent people destroyed in a cataclysm c.65 million B.C.E. which caused the surviving serpent people to migrate to Elder Valusia and aided the extinction of the dinosaurs. Shuggon is named in the Necronomicon but goes unnamed in most other texts. May be the same as Altuas or Altuan.
Shuggon was named by Lin Carter, although it was earlier implied that the serpent people went back to the age of dinosaurs.