The Mi-Go are capable of going into suspended animation until softened and reheated by the sun or some other source of heat. They can transport humans from Earth to Pluto (and beyond) and back again by removing the subject's brain and placing it into a "brain cylinder", which can be attached to external devices to allow it to see, hear, and speak.
The Mi-Go where first encountered by The Time Traveller when he travelled thousands of years into the future. At first he thought they were descendants of 19th century humanity, just like the Eloi, but later he discovered their true nature. They seem to serve the Great Old Ones since they tried to stop The Time Traveller, John Carter, Randolph Carter and Allan Quatermain from succeeding in their mission to stop creatures from beyond the universe from invading creation through a hole in space-time. They attack the four men when they are gathered inside the Time Travellers head quarters, but the group manages to fight them off. One is able to hang onto the time machine when it takes off, and damages the machine, causing it to become stranded in a chrono-crystal aleph.
The Mi-Go are a creation of horror writer H.P. Lovecraft, and appear in several stories of the Cthulhu Mythos.
The Mi-Go's appearance in the LoEG differs greatly from how Lovecraft described them. In Lovecraft's stories they are depicted as large, pinkish, fungoid, crustacean-like entities the size of a man; where a head would be, they have a "convoluted ellipsoid" composed of pyramided, fleshy rings and covered in antennae. According to two reports in the original short story, their bodies consist of a form of matter that does not occur naturally on Earth; for this reason, they do not register on ordinary photographic film. In the LoEG however they are depicted as large, albino, ape-like creatures. They also turn out to be the same species as the Morlocks, from H.G. Well's The Time Machine.
It is possible that Lovecraft encountered the word migou in his readings. Migou is the Tibetan equivalent of the yeti.