Look what ive just come across on a website:

13) Is it haram to write a book, or read one for that matter, if is a scary book, or a fiction? If you want to write fiction does it have to be clean of any non islamic ideas or values or beliefs? It seems that when I try to write fiction I am afraid of leading someone astray even though they know its a fiction.

Your concerns are well founded. One should avoid writing, distributing, or reading materials which contain non-Islamic concepts such as draculas, ghosts, etc. Such writings are lies, lead to deviant beliefs, and cause deviant behavior -- especially writings (even worse, movies) of violent nature that are used by the non-Muslims to produce thrill in their sick souls.