When the spell is done, you die and your soul is imbued in the crystal. Any creature who touches the crystal must make a Will save or have your soul possess them. You use your own supernatural and class abilities, feats, skills, and mental ability scores, but their physical ability scores, extraordinary abilities, health, and other non-supernatural, non-class traits. Exorcising you simply requires reducing you (and the host) to -5 health or less. Once you possess someone, the crystal breaks. Focus: A crystal, worth at least 500 gp.