Political Frankenstein
A politician who becomes monstrously notorious or infamous, usually for their outrageously controversial behavior or ridiculously bombastic statements. Once the resulting monster is unleashed, the media usually has a field day with it and even the powers-that-be seemingly cannot regain control of it and make it go away.
Sarah Palin and Rod Blagojevich are probably the two biggest Political Frankensteins of the past couple years.