Mind flayer An illithid , also called a mind flayer , was an evil and sadistic being , humanoid in appearance , but with a four - tentacled octopus - like head . These beings were feared throughout the Underdark for their telepathic abilities and usually were not without two or more slaves , mentally bound to each individual mind flayer . Although they cooperated to achieve a goal , they would back away at the first sign that something was not profitable to themselves . They were capable of speaking Undercommon , but preferred telepathic communication and would attempt to mentally dominate any non - slave , non - illithid they met . They fed on the brains of sentient creatures and were thus feared . Their natural psionic abilities also made them respected in the eyes of the drow , beholders , duergar , and the other dominant races of the Underdark . History . Some theorized mind flayers to be aliens from the future ( as stated in The Sargmne Prophecies ) , who had come back in time to prevent the end of the world . Facing extinction , they sent the greatest spelljamming fleet in history back in time . Due to their futuristic technology and ships , many believe that they were a cursed in - bred mutant offspring of humans from a distant world . Some even believe that signs point to a more sinister origin in the Far Realm . Powers . The mind flayers were feared by all beings in the Underdark because of their great mental prowess . Every illithid had a small array of to take control of their prey , as well as a powerful " mind blast " to affect a multitude of foes . The mind flayer ' s " mind blast " was a 60 - foot ( 20 - m ) cone that stunned anyone caught within it . The mind flayer could also innately cast three mind - affecting spells : " charm monster " , " detect thoughts " , and " suggestion " . Mind flayers were also capable of casting " levitate " and " plane shift " . Normally , a mind flayer would use its " mind blast " ability to stun a few foes and then drag them away to feed . Once it had its victims , it would attach all of its tentacles to the head of its victim . Then , the mind flayer sucked out the brains , instantly killing the victim , as long as it only had one head . The mind flayer used its other spells mainly to enslave its minions and keep them under total control , as well as on the battlefield . They also have the ability to craft psionic seal s . Society . Mind flayer communities ranged in size from two hundred to two thousand , and that was counting only the illithids . Each mind flayer in the community likely had at least two slaves to do its bidding . In these communities , the number of slaves often far outstripped the number of mind flayers . For example , the illithid city of Oryndoll had a total population of 26 , 000 , but mind flayers only account for 3 , 450 of that number . When problems arose or the mind flayers wish to discover some secret , they formed inquisitions . These inquisitions were made up of a team of mind flayers , not unlike an adventuring party — each mind flayer used their own talents and abilities to achieve the inquisition ' s goal . If a situation was too large for just an inquisition to handle , the mind flayer community put together a cult . A cult was much larger than an inquisition and was spearheaded by two mind flayers who constantly vied for greater power within the cult . Although mind flayers willingly came together to achieve an end , they were always vying for more control in the community , but even then they were always beneath the elder brain . The elder brain was the heart of the community . Held in a pool of briny fluids , the elder brain consisted of all the brains of the dead mind flayers in the community . Some mind flayers underwent a process called laceremorphosis , which made them bigger , stronger , and more powerful than regular mind flayers . They became ulitharid s or illithid - nobles , and possesed six face tentacles instead of the regular four . A urophion was a subspecies of mind flayer created as guardians for a mind flayer community . An urophion was a roper that had survived the tadpole implantation process . They were usually treated as second - class citizens but were permitted to join with the elder brain upon death . Religion . Mind flayer religion was once non - existent . In the time when they had invaded the shield dwarf kingdom of Shanatar and captured many shield dwarves , the mind flayers had no gods . Originally , their plan was to create a superior race of dwarves , skilled in both mechanics and psionics that would be loyal solely to the mind flayers . However , when the dwarves began to stage uprisings and rebellions , the city of Oryndoll , where the experimentation was occurring , was plunged into chaos . The only reason the city did not fall to the duergar rebellions was because of the sudden appearance of the mind flayer god Ilsensine . Since Ilsensine ' s appearance , the mind flayers became deeply religious and began to develop the formidable psionic powers that the race was known for . Ilsensine ' s favored proxy was Lugribossk . Mind flayers once had an additional god called Maanzecorian , who was killed by Tenebrous , the undead shadow of the demon lord Orcus , though this fact was unknown to most . Illithid magic . Although most mind flayer arcanist s were wizards , a few were also born with the gift of sorcery . Because a mind flayer sorcerer was naturally more intelligent than other mind flayers , it was better able to resist psionics . For the most part , an illithid with the gift of sorcery would use defensive spells such as " greater invisibility " and " resist energy " as well as spells to further hinder enemies , such as " ray of exhaustion " and " touch of idiocy " . A mind flayer who decided to follow the path of wizardry could become an undead creature known as an alhoon or an illithilich .