Incubus is a novel written by Ray Russell. It was first published in 1976. It was adapted into a film in 1982.
Description[]
Galen is an ordinary, peaceful small town. Until horrendous terror strikes...and strikes again and again, each time claiming a female victim in a fashion too hideous to contemplate. Julian Trask, student of the occult, is used to thinking the unthinkable. As he works towards the solution of the soul-searing mystery, Galen trembles in mortal dread. For no woman is safe from the lethal lust of THE INCUBUS.