Desiring to be one of Arthur's organs... not something as metaphorically significant as his brain or his heart; something less often considered nestled within him, doing its part to keep him alive.

His liver, cleaning toxins from his blood, or his lungs, expanding and contracting with the force of his breath. A full system, maybe - skeletal, nervous, circulatory - spidering through his body and contorting with his movements. His spinal cord would be ideal; curving down the length of his torso, hugged by his vertebrae, surging with the electrical energy of his thoughts. His eyes are off limits (they belong to the man with the painted face) but I can imagine being them, rapid in movement and hungry for light. Translating everything around him into two colorful dimensions.

Ultimately the desire is to be so close that I'm a part of him, useful but quiet. Pulsing within the sauna of his body until it grows cold in death.