Dadajef said:
You discard the IO (It's written on the card > if the control of the IO change, discard it). If the attached character was committed, you removed it from the story (you regain the control of your character) as says the faq : " Any time a player gains control of a committed character during a story, that character is removed from the story ."
Attach to a non-Ancient One character.
While attached, you gain control of attached character. (If control changes again, discard Infernal Obsession from play.)
I thought "If control changes again" means the attached character not the Infernal Obsession by itself.