A horrible torture device. Not for the squeamish.
There are a lot of bad people out there. That is why we must torture you: to keep you safe.
Many and varied are the ways of extracting a confession or ending a criminal’s life, and the one usually follows the other.
Magic is a blessing and curse, life and death, birth and undoing, a goal and a way.
What if a mage passes his powers on to his firstborn son, and a female mage to her first daughter, leaving the parent POWERLESS? A plain mortal, a sorcerer no longer, all wizardly might gone?
Or: what if a female wizard recieves the power of a mage who sires a child with her? Could lead to promiscuous witches and overly careful mages.