The kogukhpuk is a subterranean creature from Yupik tradition.
These creatures are alternatively described as massive or not much larger than a muskrat, but either way they have large tusks protruding from their mouths. An illustration of such a creature depicts them as bulbous creatures with wide, toothy mouths and frog-like legs.
Kogukhpuk once roamed the earth, but they went underground either of their own volition or by the hand of a powerful shaman. The sunlight is so toxic to them that they will die instantly at the slightest exposure. As a result, they spend most of their time burrowing underground (the name kogukhpuk means "earth mole"), but will emerge on the winter solstice to feed. The bones of mammoths are said to be the remains of kogukhpuk caught above the surface at dawn.
They sometimes burrow close to the surface and cause cave-ins and flooding. They're also excellent swimmers, and so this poses little problem to them. Kogukhpuk that venture too close to villages can wreak havoc on them and destroy buildings with their digging.