The mind flayer appears first in the Monstrous Compendium Volume One (1989), and is reprinted in the Monstrous Manual (1993). Advanced Dungeons & Dragons 2nd edition (1989–1999) The "Dragon's Bestiary" column, in the same issue and by the same author, described the illithidae, the strange inhabitants of this world. The article "The Sunset World" by Stephen Inniss in Dragon #150 (October 1989) presented a world that had been completely ravaged by mind flayers. Moore authored "The Ecology of the Mind Flayer," which featured in Dragon #78 (October 1983). The mind flayer appears in the first edition Monster Manual (1977). Advanced Dungeons & Dragons 1st edition (1977–1988) They were also included in the Eldritch Wizardry supplement, for the original (white box) Dungeons & Dragons game (1976), wherein they are described as super-intelligent, man-shaped creatures of great (and lawful) evil, with tentacles that penetrate to the brain and draw it forth for food. A mind flayer's major weapon is given as the Mind Blast, a 5-foot radius wave of "PSI force" which affects each opponent differently based on how intelligent it is possible effects include permanent insanity, rage, confusion, coma, and death. Here, the mind flayer is described as "a super-intelligent, man-shaped creature with four tentacles by its mouth which it uses to strike its prey." When it hits prey with a tentacle, the tentacle penetrates to the brain and draws it forth, allowing the monster to devour it. Mind flayers first appeared in the official newsletter of TSR Games, The Strategic Review #1, Spring 1975. Tim Kirk's cover art on the book, then in its first printing, depicted only the tentacles of the titular burrowers, the Chthonians. Mind flayers were created by Gary Gygax, who has said that one of his inspirations for them was the cover painting of the Titus Crow book The Burrowers Beneath by Brian Lumley. The illithid is considered "Product Identity" by Wizards of the Coast and as such is not released under its Open Game License. Illithids are well known for making thralls out of other intelligent creatures, as well as feasting on their brains. Illithids believe themselves to be the dominant species of the multiverse and use other intelligent creatures as thralls, slaves, and chattel.
In a typical Dungeons & Dragons campaign setting, they live in the moist caverns and cities of the enormous Underdark. In the Dungeons & Dragons fantasy role-playing game, illithids (commonly known as mind flayers) are monstrous humanoid aberrations with psionic powers.