'Black Finger'
A rare genetic disorder. A mixture of telekinesis and brain manipulation. It usually occurs in the highly intelligent and mentally disturbed children and advances slowly though childhood.
It begins, with a black finger,at birth, which then slowly turns the pale white where therein, it can send out various brainwaves. The brain-waves have been known to be changed. No two 'Black finger' infections are the same, one for instance, can simply point, and the victim dies, while another points his finger, and the victims brain explodes, however they are all malevolent brain-waves.
David's infection is honed to be of a torture technique, it uses mental sparks of pain. That spread like fast growing roots throughout the body, thus extricating pain. That amplifies with every negative thought.
The victim must learn to love David.