Mi-go are a fictional race of extraterrestrials created by H. P. Lovecraft and used by others in the Cthulhu Mythos setting. The word Mi-go comes from "Migou", a Tibetan word for yeti. The aliens are fungus-based lifeforms that look like winged humanoid crabs, and do not resemble yeti.
Mi-go are first named as such in Lovecraft's short story "The Whisperer in Darkness" (1931). However this is considered an elaboration on earlier references in his sonnet cycle Fungi from Yuggoth (1929–30) to descriptions of alien vegetation on dream-worlds.
The Mi-go have appeared across a range of media set in the Cthulhu Mythos.
The "Mi-go" are 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. They are about five feet (1.5 m) long, and their crustacean-like bodies bear numerous sets of paired appendages. They possess a pair of membranous bat-like wings which are used to fly through the "aether" of outer space (a scientific concept which is now discredited). The wings do not function well on Earth. Several other races in Lovecraft's Mythos also have wings like these.
In the original short story, the creatures cannot be recorded using ordinary photographic film, due to their bodies being formed from otherworldly matter. They are capable of going into suspended animation until softened and reheated by the sun or some other source of heat. The Mi-go 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" as an isolated brain, which can be attached to external devices to allow it to see, hear, and speak.
In "The Whisperer in Darkness" the Mi-go are heard to give praise to Nyarlathotep and Shub-Niggurath, suggesting some form of worship. Their moral system is completely alien, making them seem highly malicious from a human perspective.
One of the moons of Yuggoth holds designs that are sacred to the Mi-go; these are useful in various processes mentioned in the Necronomicon. It is said that transcriptions of these designs can be sensed by the Mi-go, and those possessing them shall be hunted down by the few remaining on earth.
Supposedly, a group known as the Brotherhood of the Yellow Sign are dedicated to hunting them down and exterminating the fungoid threat, though it is unknown if this is actually true since it was given as a reason for their remaining hidden. Hastur, which is mentioned in passing among several other places and things, was eventually converted into a God-Like alien being by August Derleth who gave it the title "Him Who is Not to be Named". However, in "The Whisperer in Darkness", a human ally of the Mi-go mentions "Him Who Is Not to Be Named" in the list of honored entities along with Nyarlathotep and Shub-Niggurath. Lovecraft never made a connection between Hastur and "Him Who Is Not to Be Named", and indeed didn't even imply Hastur was a being; Derleth was the one to do so.
The Mi-go appear in the Lovecraft novella At the Mountains of Madness (1931), in which they are described as having made war with the Elder Things long before the existence of humans.
The Mi-go appeared in comic books in the first three issues of H. P. Lovecraft's Cthulhu: The Whisperer in Darkness that featured the Miskatonic Project, created by Mark Ellis.
The Mi-go are prominent antagonists in Pagan Publishing's Delta Green sourcebook for the Call of Cthulhu role-playing game. It mentions three castes: scientist, soldier, and worker. The book states that the Mi-go usually have five pairs of appendages, though the number can vary. Normally, the first pair is designed for grasping and manipulating, but in the scientist caste it is usually the first two pairs. The remaining appendages are used for locomotion. The soldiers may have two or more pairs of wings. Some individuals do not have wings at all if they are deemed unnecessary to their task. The Mi-go apparently can modify their own bodies. This source suggests that all their external accoutrements are actually extruded at will from the central gelatinous mass similar to the way the Shoggoth extrude body parts. In the Delta Green setting, the "Greys" are puppets remotely controlled by the Mi-go.
They are distinguished by their mastery in various fields of science, especially surgery. Although they originate from beyond our solar system, they have set up an outpost on Pluto (known as Yuggoth in the mythos) and sometimes visit Earth to mine for minerals and other natural resources. The Mi-go normally communicate by changing the colors of their orb-like heads or by emitting odd buzzing noises. They can also speak any human language upon receiving the appropriate surgical modification.
The Mi-Go are one of the main enemies of humanity in the role-playing game CthulhuTech, which combines Lovecraft's fiction with tropes and themes from mecha anime. In the game, their name is spelled “Migou” (see below), but they are commonly referred to as bugs by humans.
They are presented in CthulhuTech much as they are in the original Lovecraft stories, and somewhat similar to that in Delta Green: they are masters of science and genetics, and in particular human genetics. Their hostility to humanity could be seen as jealousy that humans had created a technology which they had never thought of, combined with a fear of humanity's growing power. Although it is stated that they have emotions vastly different from our own, their campaign on Earth developed into genocidal hatred of humans.
In Allan and the Sundered Veil, Allan Quatermain, Randolph Carter, John Carter of Mars, and the Time Traveller encounter the Mi-go, which are stated to be the same as Morlocks and the Yetis.
In "To Mars and Providence", the Mi-go engage in trade with the Martians from The War of the Worlds.
The Mi-go appear in the final segment of the movie Necronomicon, directed by Brian Yuzna.
A Mi-go is scripted to walk across the stage during the "Tentacles" number of A Shoggoth on the Roof, prompting Armitage to say "some horrible creature... I do not even want to know what that is".
The horror-themed miniatures game HorrorClix, which features Cthulhu as a colossal figure, includes a Mi-Go as a unique figure in its The Lab expansion.
The Mi-Go also appear as sinister brain collectors in the short story "Boojum", written by Sarah Monette and Elizabeth Bear.
The computer game Cataclysm: Dark Days Ahead features the Mi-go among the numerous different types of monster that assault the earth. This Mi-go appears to be inspired by, rather than lifted from, the original Lovecraftian creature, since their unique feature in the game is to mimic human speech and other sounds in an attempt to lure people towards them.
It is possible that Lovecraft encountered the word migou in his readings. Migou is the Tibetan equivalent of the yeti, an ape-like cryptid said to inhabit the high mountain ranges of that region. While the Mi-go of Lovecraft's mythos is completely unlike the migou of Tibetan stories, Lovecraft seems to equate the two, as can be seen in the following excerpt from "The Whisperer in Darkness":
It was of no use to demonstrate to such opponents that the Vermont myths differed but little in essence from those universal legends of natural personification which filled the ancient world with fauns and dryads and satyrs, suggested the kallikanzarai of modern Greece, and gave to wild Wales and Ireland their dark hints of strange, small, and terrible hidden races of troglodytes and burrowers. No use, either, to point out the even more startlingly similar belief of the Nepalese hill tribes in the dreaded Mi-Go or "Abominable Snow-Men" who lurk hideously amidst the ice and rock pinnacles of the Himalayan summits. When I brought up this evidence, my opponents turned it against me by claiming that it must imply some actual historicity for the ancient tales; that it must argue the real existence of some queer elder earth-race, driven to hiding after the advent and dominance of mankind, which might very conceivably have survived in reduced numbers to relatively recent times—or even to the present.