Ceremorphosis

"Brains! Once an illithid gets its first taste of 'the other white meat', there's no going back."

- S. Wakeman

Ceremorphosis was a bodily change that occurred when an illithid tadpole reached maturity and was inserted into the brain of another humanoid being, usually a human. The tadpole ate away the victim's brain matter and essentially replaced the brain, erasing all of the subject's personality and memory, but leaving the physical body alive and under the tadpole's control. After this, morphological transformations occurred and after a week a new illithid was created.

It was common for the newly formed illithid to retain a few memories of its former host. Those memories were merely vestigial and rarely affected the new individual's personality.

Description
Upon securing a suitable host, mind flayers began the procedure by rendering the candidate docile with a mind blast. A mature tadpole, selected after surviving a period of one decade in the elder brain's brine pool, was then inserted in the host's cranium through a nostril or ear canal. It then burrowed into the brain and quickly devoured the gray matter, growing in the process as it replaced the brain with its own tissue and attached itself to the brain stem like a parasite. This initial process, which happened over a period of a few hours, effectively completely replaced the victim's personality with the tadpole's, while still keeping the body alive for the second stage of the transformation.

It was only possible to interrupt ceremorphosis and save the host before this initial stage was completed, and even so it was only possible to do so by killing the tadpole, which was complicated by its location. The safest way was to incinerate or crush the host's head and then use spells such as resurrection, or true resurrection. Destroyed parts of the victim's personality could then be reconstructed via restoration and heal spells, as long as the damage was not complete.

After the initial stage was completed, the original creature was lost and beyond help, except for a miracle. Over a period of approximately one week, the host's body underwent extensive morphological and tissue changes, completely transforming into a mind flayer. Internal organs were reshaped, but retained their original purpose. Until ceremorphosis was completed, the emerging mind flayer remained helpless.

The newly formed mind flayer, despite being fully grown, was equivalent to an infant, and had to undergo a period of instruction and experience that lasted approximately twenty years, usually within the confines of a secure illithid city.

The physiological changes caused by ceremorphosis played a key role in the illithids' dietary habits. Since the tadpole acted more like a parasite of its host's body than a proper brain, it did not produce the enzymes and psychic energy necessary to keep it alive. These essential nutrients needed to be acquired through consumed brains for the body to survive.

Acceptable Hosts
The success of ceremorphosis was only guaranteed with a few humanoid races. In particular, only humans, elves, drow, githyanki, githzerai, grimlocks, gnolls, human-sized goblinoids, and orcs produced viable mind flayers. In addition, the candidate's height and weight also played a role in the process, since body mass was a factor in the tadpole's growth rate. Only humanoids weighing between 130 and 270 pounds (60‒120 kilograms) and with heights between 5 feet 4 inches and 6 feet 2 inches (1.62‒1.88 meters) were considered acceptable. Creatures outside that range caused the tadpole's evolution to proceed either too fast or too slowly, and both cases resulted in both the host's and the tadpole's death.

Some creatures were always considered unacceptable for ceremorphosis. Those included centaurs, derro, duergar, dwarves, giants, gnomes, halflings, and kuo-toa. Any attempt to conduct ceremorphosis in one of those races invariably resulted in death for the host and the tadpole. Most non-mammalian species were also considered incompatible in principle.

Since the height and weight ranges were a more determinant factor than species in the success of ceremorphosis, in principle even other races that fell within those ranges could still be compatible. For that reason, mind flayers constantly conducted experiments with newly found creatures.

Half-illithids
A small variety of species could successfully undergo ceremorphosis, but if not one of the fully compatible races, the result was called a "half-illithid" or "ceremorph". They did, however, still possess most of the powers of a regular illithid. Examples of creatures that had undergone ceremorphosis successfully included:


 * Brainstealer dragon
 * Mindwitness
 * Mozgriken
 * Tzakandi
 * Uchuulon
 * Urophion

An illithid tadpole that survived but was not submitted to ceremorphosis was called a neothelid.

History
Some sages believed that ceremorphosis had been a late development in the evolution of the mind flayer species. Evidence of this was found in the shape of their two-toed webbed feet, which suggested a pre-ceremorphic race of water dwellers.