They appear in several dungeons, such as Flying Fortress, the Cavern of Ice, and the Chaos Shrine. They are dangerous foes, as they have some potent special attacks. Its physical attack, while doing only one point of damage, may cause Instant Death. They also have high Magic Defense, making them hard to hit with magic, and they do not have any weaknesses. Physical attacks are the way to go, but their Mind Blast ability can target the party's physical fighters, which in turn can hinder the player's fleeing abilities.
Mindflayers, or "Illithids," are a race found in Dungeons & Dragons. They appear humanoid, with heads that resemble octopuses, and frequently are found in the Underdark. They have fearsome psychic powers, subsist on a diet comprised of the brain tissue of sapient beings, and often enslave other races.
- Like so many enemies in Final Fantasy's bestiary, Mind Flayers are taken directly from the bestiary of Dungeons & Dragons, and are one of the most infamous and iconic monsters of that game.
- While the "Evil Eye" (AKA a Beholder) was drastically changed in appearance in every single release after the initial Japanese one due to copyright concerns, Mind Flayers have not been renamed or graphically altered, despite their prominence in Dungeons & Dragons, and have appeared in other games since. One general assumption is that, so long as the Mind Flayers are not called "illithids" (which is a specifically-protected term), Wizards of the Coast cannot claim copyright infringement, as the concept of the "octopus-faced mind eater" comes from still earlier works by Brian Lumley and H.P. Lovecraft.