The Magic Finger by Roald Dahl

The Magic Finger is narrated by an eight-year-old girl (voiced by Anne Clements in the United Kingdom) growing up on a farm in the English countryside, next door to the Gregg family who have a passion for hunting. The titular "Magic Finger" is an ability she has that activates inadvertently whenever she gets intensely angry: the finger shoots out a beam of energy that apparently seeks out whoever has angered the girl, with unpredictable consequences. One day, the girl sees Mr. Gregg and his two sons returning home from a hunt with a deer they have killed, and they make fun of her when she admonishes them. In a rage, she puts the Magic Finger on the entire family: they wake up the following morning to find that they have shrunk to the size of birds and developed wings in place of their arms. While trying their wings, the Greggs fly out of their house, which is promptly occupied by a family of human-sized ducks with human hands, and they are forced to make a nest in an old tree for the night.