Nightstar is Ethel Hallow 's cat. Like most of the other cats, he is black all over. Nightstar is very good at flying. He sits on Ethel's broomstick as if he is a model glued down. He is so good that he puts all the other cats to shame. Even when not on the broom, Nightstar sits bolt upright and still like a statue. Nightstar is very protective of Ethel. When Mildred Hubble's cat Tabby ended up on Ethel's broomstick, he kept on swiping down on his guest.
"Almost all the first-year witches were in the yard trying to persuade their puzzled kittens to sit on their broomsticks. Several were already clinging on by their claws, and one kitten, belonging to a rather smug young witch named Ethel, was sitting bolt upright cleaning its paws, as if it had been broomstick riding all its life!"- The Worst Witch