Illithid

From NWNWiki

Also known as mind flayers, these tentacled monstrosities are generally weak of body but strong of mind. Their unmatched psionic attacks can paralyze an opponent, giving the mind flayer ample time to wrap its tentacles about the victim's head to suck out their brains. Most heroes die from the procedure. Mind flayers are also capable of creating realistic illusions that are rather difficult to disbelieve. They live in the moist caverns and cities of the enormous Underdark. Illithid believe themselves to be the dominant species of the multiverse and use other intelligent creatures as thralls, slaves, and cattle.