The Gruffalo by Julia Donaldson

A mouse is taking a stroll through the deep, dark wood when along comes a hungry fox, then an owl, and then a snake. The mouse is good enough to eat but smart enough to know this, so he invents . . . the gruffalo! As Mouse explains, the gruffalo is a creature with terrible claws, and terrible tusks in its terrible jaws, and knobbly knees and turned-out toes, and a poisonous wart at the end of its nose. But Mouse has no worry to show. After all, there's no such thing as a gruffalo. . . .