Yuggoth

Yuggoth (or Iukkoth) is a fictional planet in the Cthulhu Mythos of H. P. Lovecraft. It is deemed to be located at the very edge of the Solar System.

Links with Pluto

At the time of the discovery of the planet Pluto in 1930 Lovecraft himself very casually suggested, in a letter to a friend, that Yuggoth might "probably" be the same as Pluto . Other writers have since claimed that it is actually an enormous trans-Neptunian world that orbits perpendicular to the ecliptic of the solar system. The Italian astronomer Albino Carbognani has suggested that any planet discovered beyond Pluto might be named Yuggoth.

In the Cthulhu Mythos

Yuggoth... is a strange dark orb at the very rim of our solar system... There are mighty cities on Yuggoth—great tiers of terraced towers built of black stone... The sun shines there no brighter than a star, but the beings need no light. They have other subtler senses, and put no windows in their great houses and temples... The black rivers of pitch that flow under those mysterious cyclopean bridges—things built by some elder race extinct and forgotten before the beings came to Yuggoth from the ultimate voids—ought to be enough to make any man a Dante or Poe if he can keep sane long enough to tell what he has seen...
—H. P. Lovecraft, "The Whisperer in Darkness"