The mind flayer, also called the illithid, is an evil and sadistic being, humanoid in appearance, but with a four-tentacled octopus-like head. These beings are feared throughout the Underdark for their telepathic abilities and usually are not without two or more slaves, mentally bound, to each individual mind flayer. Although they cooperate to achieve a goal, they will back away at the first sign that it is not something that will be self-profitable.
They are capable of speaking Undercommon, but prefer telepathic communication and will attempt to mentally dominate any non-slave, non-illithid they meet.
They feed on the brains of sentient creatures and are thus feared. Their natural psionic abilities also make them respected in the eyes of the drow, beholders, duergar, and the other dominant races of the Underdark.