HOB.

Under the stairs in the house where Boy and Girl live there is Hob, a little helper. He always gets a gift each night, like an apple or an egg. And in return he drives away things that not supposed to be in the house, like Clockstop who stops clocks from going right, and eats time. Also he scares away Wump--who stomps down the stairs breaking them, tipping over bottles, denting the house, knocking out a brick, and making Hob's teeth rattle. In that episode he asks Budgie the pet bird to sing Baby to sleep. She sings, "Go to sleep, little egg." "The bird's an idiot," says Hob.

The Hob stories come in the red, yellow, green and blue books, or you can get all of them in one book, that is the book shown. Also you can get Hob and the Goblins as well as Hob and the Peddler. They are longer and have chapters.
HOB is by William Mayne, and illustrated by Patrick Benson. The pictures are so beautiful.