Yuggoth is a planet within the solar system that Earth is also within, sometimes thought to be Pluto or some planet beyond. Yuggoth is the home of the living fungi, the Mi-Go. The colony of Mi-Go upon Yuggoth exist right next to a pit, where a being rests. The Mi-Go are, for some reason, terrified of this being, and often evacuate the city when it awakens.
The Mi-Go mine a strange metal known as Tok'l. They use this metal for rituals and for constructing their infamous "Brain Cylinders ."