What is a good Children's Horror Book Series?

I Prefer a Series of Childrens Horror Books that tell One Story (Things like "The Saga of Darren Shan" by Darren Shan and no, its not an autobiography, the main and character's name is same as the authors / "Harry Potter Series" by J.K.Rowling) I like a series that is scary and less than 10 Books. Thanks for You Help :)