An epithet often given to Hastur by post-Lovecraft writers and derived from Magnum Innominandum. It should more correctly be the Unnameable and can be rendered as He Who Must Not Be Named. Somewhat incorrectly, but thematically suitably, it has been taken to mean that Hastur should not be named due to the risk of attracting his attention - in one Dungeons & Dragons supplement this was extended to merely speaking his name aloud causing Hastur to appear and attack. August Derleth extended the concept to what became known as the Unspeakable Oath.