Black pearls - rare and valuable.

They are also untraceable.

And so one evening a congregation of coaches decided that certain players should not be allowed on the pitch. Players that had been augmented to the extent that something had to be done. So they pooled their resources to buy some of the most valuable stones on the planet.

Should someone make their way onto this list, their days will be numbered. For should they be killed or retired, their assailant will be rich beyond their wildest dreams.