All is calm in the Wormwood household for a week following the hat incident, and Matilda wonders if her trick had been enough to finally stop her father from bullying her. Then one evening he returns from work, clearly in a sour mood, and snaps at Matilda for choosing to read a book instead of watching television. He tears pages from her book and throws them in the trash can, which leaves her shocked and angry, since it is a library book and does not belong to her. While Matilda is extremely upset, she realizes the only way to deal with this is to get back at him.
With a plan in mind, Matilda goes over to her friend Fred's house the next day to investigate his talking parrot, wondering if it talks as well as he says it does. The parrot's voice does indeed sound just like a human's, but he can only say "Hullo" and "Rattle my bones!" Matilda decides this is enough for her purposes, and gives Fred all her pocket money so that he will loan the parrot to her for just one night.
Once home, she wedges the parrot's cage up the chimney so it cannot be seen. That evening, as the family is eating dinner in front of the television, the parrot begins to speak. It says "Hullo, hullo, hullo" over and over again, and Matilda's mother panics because she thinks burglars are in the house. She insists that Matilda's father go check, but he is afraid, so he drags the rest of the family with him. Unsurprisingly, they find no one, but the parrot begins to say "Rattle my bones." Matilda guesses aloud that it is a ghost, and proclaims that the room is haunted. The family runs out of the house in fright, and the next day Matilda is able to take the grumpy, sooty parrot down from the chimney and return him to Fred.
Matilda takes satisfaction in the fact that her punishments seem to work, for a little while, at making her parents more bearable to be around. But it does not last. After a day of work, Mr. Wormwood asks Matilda's brother to fetch a pad and paper to add up some figures, since he will be joining his father's car sales business when he is older and will need to know these things. He lists how many cars he sold that day, stating both the price he bought them for and the price he sold them for, and asks his son to figure out his final total profit. In hardly a blink of an eye, Matilda answers, getting the number exactly right. This rattles her father, who calls her a liar and a cheat.
Matilda knows her father needs another punishment. She takes her mother's platinum blonde hair dye from the cupboard in the bathroom and pours some of it into her father's bottle of hair tonic, which he uses to keep his thick black hair looking bright and strong. She listens in the morning while he applies it, and he is clearly unaware that anything is amiss. Then he comes into the kitchen to eat his breakfast, and Matilda's mother screams when she catches sight of her husband, with hair that is now a dirty silver color. She insists he must have dyed it, and Matilda suggests that he unwittingly took Mrs. Wormwood's bottle of hair dye off the shelf instead of his own tonic.
They all tell him to wash his hair fast or it might start falling out, since peroxide is a powerful chemical. Matilda plays innocent, and her mother tells her that she will learn as she gets older that men are not quite as clever as they think they are.
Roald Dahl's writing style is unique, in that it uses simple, short sentences to make it sound as if it is a story being told aloud. This fits the book's genre, since children's stories are very often narrated aloud to young listeners in a way that captivates their attention. Because Matilda is such an advanced child, however, he takes care to insert more complex vocabulary words, like "incapable" and "devouring" to ensure that older readers can remain interested as well.
Matilda is still a young child, so it would be understandable for her to grow frustrated and upset with her parents' treatment of her and lose control of her emotions. This is especially true of the library book incident; books are extremely important to her, so to see her father completely disregard them and tear one up is rightfully disconcerting. However, one of the primary ways in which Dahl distinguishes Matilda from typical children her age is her emotional response to taxing situations. Rather than fly off the handle, Matilda recognizes that sorrow and tears will not solve the problem, and instead calculates ways that she can actually elicit a change in her parents' behavior. This shows maturity far beyond her years.
There is a clear juxtaposition present between Matilda and her father when it comes to emotional control and stress response. When Mr. Wormwood is in difficult situations he loses his cool, shouting and demeaning his family and completely losing control. Matilda, however, can keep herself collected and calm, even when inside she is boiling with anger, and this stability allows her to think and reason through trouble. Once again, Dahl flips around the typical behaviors associated with age, showing that adults are not necessarily more rational than children.
Matilda and her brother Michael are juxtaposed in a similar way. Once again, age does not necessarily correlate with wisdom; Matilda is far more intelligent than her brother, though she is the younger child. It is ironic that Michael is the one who is being invited to join the family business with their father when he gets older, even though Matilda is clearly the smarter one who can is far better at using numbers in the way a salesperson must. The difference in their parents' treatment of Matilda as opposed to Michael confirms the common notion that familiarity breeds fondness. Matilda's parents are kinder and more loving to Michael because he is like them in many ways, in terms of interests and intelligence level. Matilda is far different, and because they do not understand her, they push her away.
Matilda's trickery not only manipulates her father's treatment of her, but it also further transforms her family dynamic. This is evident in the hair dye scene, when Matilda and her mother connect over her father's apparent foolishness. By putting her father in compromising situations, Matilda manages to become closer to her mother as they laugh or shake their heads at him, which disrupts the typical family dynamic even more and ensures that Matilda is no longer the one who is subject to ridicule.