The malefactors in Roald Dahl’s fiction are easy to spot. “If a person has ugly thoughts, it begins to show on the face,” the author writes in The Twits . “And when that person has ugly thoughts every day, every week, every year, the face gets uglier and uglier until you can hardly bear to look at it.” Miss Trunchbull, the abusive headmistress of Matilda , is a “gigantic holy terror” with “an obstinate chin, a cruel mouth and small arrogant eyes.” Augustus Gloop, the greedy glutton of Charlie