The Devouring by Simon Holt
If you are looking for something scary this month give The Devouring by Simon Holt a try. This book felt like I was reading a horror movie. It may give you nightmares, so please don't say I didn't warn you!
Reggie is a horror fanatic. When she finds a journal in a box of used books at the bookstore where she works, she "borrows" it. It tells of the Vours, black smokelike beings that possess humans who can't conquer their fear on Sorry Night (the eve of the winter solstice). Reggie and her friend Aaron attempt to make the Vours materialize but instead they possess her little brother. In a fight to the death, Reggie joins the battle of humanity against the Vours.