Pencil is graphite encased in wood.
A pencil is a rod of graphite bound in a wood body, which can be made in various degrees of hardness. Graphite is a metal grayish color and is often used for underdrawings but can also be used to create soft lines and edges, differentiating it from inks or charcoal pencils.
Stephen Gammell: Terrible Things
The year before illustrating Scary Stories to Tell in the Dark, Gammell illustrated Terrible Things by Eve Bunting. These pencil drawings of everyday birds, squirrels, rabbits, frogs, fish, and porcupines depict those who do nothing in the face of injustice. When the terrible shadows swing, drag, thunder, and carry away the animals, the reader may be reminded of the familiar drawings associated in Gammell's later works such as Scary Stories. Gammell’s pencil illustrations contrast between the precisely drawn animals and the smudged and streaked Terrible Things moving across the page, giving the reader a sense of lurking fear and terror.