Discworld Challenge

Perspicacia Tick is a "witch finder", a travelling witch with the responsibility of finding young girls who have the potential to be witches. She makes a living as a teacher, a role which has given her a habit of correcting spelling, grammar and punctuation. Since she often finds herself in areas where witches are unwelcome, she has a spring-operated hat that only grows a point when she wants it to. Thanks to her time as a student at the Quirm College for Young Ladies, which views time in cold water as character-building, she has also mastered the ability to stay underwater for prolonged periods, allowing her to escape punishment from superstitious witch-hunters. To aid her in this endeavor, she is the anonymous author of Magavenatio Obtusis (Witch-hunting for Dumb People), which she generously places in the libraries of various witch-hating villages. It includes such vital information as drowning rather than burning a witch, ensuring that the witch has silver coins in her boots, and is given a nice meal of soup and tea before her ducking. Possibly the reason she must spend so much of her energy avoiding hate and harassment, rather than accepting donations of gratitude as other witches do, is that she spends much of her time travelling in areas where witches aren't welcome, looking for girls suitable to becoming witches.