What magical object does Rita Skeeter use to spy on students?

Quick-Quotes Quill

Which animal is known as Africa's deadliest mammal due to its aggressive nature? Which central Asian nation has Bishkek as its capital? Who was the King of England reigning when the English Civil War began in 1642? What flavor cheesecake do Chandler and Rachel repeatedly steal? Which metal increases steel's resistance to rust when alloyed?