Elder Brains are massive brainlike monsters from Dungeons & Dragons. These horrific creatures are the final stage of the Illithid life cycle and serve as the leaders of illithid communities.
Elder brains look much like huge human brains with black tentacles. They bare no resemblance to the Illithid monster. They are immobile because they have no way of moving.
Elder brains are strong users of psionics and use these powers to dominate foes. It senses and reads the minds of intruders long before it attacks. When it infiltrates a mind, it alters perception and fools its senses. It can plant hypnotic suggestions and compelling dreams in the brain of any sentient being. When this psychic control fails to work, the Elder brain takes total control of a resistant mind. If a creature's will is still strong, the Elder brain sends a powerful psychic blast to cause the creature to become a mindless shell. Without this psychic power, there would be no use of an Elder brain.
Elder brains are not a separate species from a mind flayer, and are born when a Ulitharid dies and mind flayers place its body in a dissolving corpse of the Ulitharid and surrounding area, which forms into the brine pool all Elder brains live in. After a time, the brain will grow and develop into an Elder brain.