If a mind flayer tadpole enters the brain of a troll, either through a nostril or ear canal, the process of turning into a mind flayer is warped by the strange abilities of the giant species. The process of ceremorphosis is a difficult and long process that can end in multiple outcomes, all of which are harmful to either the troll, the tadpole, or both creatures. 

There are many difficulties with the process, due to the regenerative nature of trolls. When a mind flayer tadpole begins to consume and replace the brain of a troll, the troll regenerates too much of its lost tissue for the tadpole to successfully complete ceremorphosis on its own. In order to completely transform the troll into a mind flayer, the troll has to be restrained and partially burnt or dissolved by acid at a consistent rate in order to slow this regeneration ability enough to allow the process of ceremorphosis to be completed. 

When the process is completed, the tall, lanky, green-skinned troll is fully transformed into purple-colored, muscular, tall, regenerative mind flayer known as a troll illinad. These mind flayers are less intelligent, wise, and charismatic than the average mind flayer, but are physically superior in every way to a typical illithid. An illinad is a towering monster who uses its long tentacles and raking claws to attack, mentally harm, and restrain their victims as they begin to devour their brains. They also can use a burst psychic energy to paralyze their victims that help them in combat. During the process of becoming a mind flayer, they make greater use of the mind flayer's inherent psionics, and use this power to ignore and absorb psychic energy.

As trolls are fairly uncommon, most mind flayer colonies do not have any illinads among their ranks. When they do manage to find a troll, they often will stun or charm the giant, bringing it back to their colony to experiment on the creature or occasionally create an illinad. When an illinad is created, they are used by the colony as guards, hunters, or brutish fighters when sent after a specific target. They are prized due to their regenerative nature, their ability to heal from psychic powers, their ability to track other creatures, and their physical strength.