Revenge of the Shadow People is a novella written by R. L. Stine and Jahanna N. Malcom. It was first published in 1996 and is the ninth book in the Ghosts of Fear Street book series.
Description[]
Afraid of your own shadow? Vinny Salvo is. Lately weird things have been happening to his shadow. It's grown horns. And claws. And big sharp teeth! Now it's coming after him!
Vinny needs someplace to hide -- and quick.
But where can you hide from your own shadow?