D&Dtools1

You cause the cyst of a subject already harboring a necrotic cyst (see spell of the same name) to envelop a portion of the victim's brain.
If the subject succeeds on his saving throw (the subject's cyst-derived saving throw penalty against effects from the school of necromancy applies), you may still influence him by suggesting a course of activity (limited to a sentence or
two).
The instruction must be worded in such a manner as to make the activity sound reasonable.
Asking the creature to stab itself, throw itself onto a spear, immolate itself, or do some other obviously harmful act automatically negates the instruction.
The instructed course of activity can continue for the entire duration.
If the instructed activity can be completed in a shorter time, the instruction ends when the subject finishes what he was asked to do.
You can instead specify conditions that trigger a special activity during the duration.
If the condition is not met before the spell expires, the activity is not performed.
If the subject fails his saving throw, the cyst envelops a larger portion of the subject's higher brain, and you gain complete control of the actions of the subject permanently.
You do not know what the subject is experiencing and share no special link with him.
If a common language is shared, you can force the subject to perform as you desire, within the limits of his abilities.
If no common language is shared, you can communicate only basic commands, such as "Come here", "Go there", "Fight", and "Stand still".
A subject may resist this control, but the presence of his necrotic tumor on his brain stem ensures their loyalty.
Protection from evil or a similar spell does not protect the subject from following your commands—the tumor is already inside him.
Focus: Caster must possess a mother cyst (see page 28).