A box of paints and a paintbrush that, when picked up, cause the user to enter a trance-state, and will begin painting on any nearby surface. The person can not be pulled out of the trance state, and will not stop until the painting has been completed. If the painter has survived through the trance, they will have no memory of painting the image, and will have gone completely insane, obsessed with drawing crude recreations of the painting.
Tell me what you think. Obviously, this is just an idea right now, so I don't want to get too invested in it if no one likes it. Also, If anything similar has been done, let me know.