The Ghost of Graylock by Dan Poblocki

I read a book called The Ghost of Graylock by Dan Poblocki and I loved it! This book is about a group of teenagers who are bored one night and decide to go to an old abandoned mental institution, but strange things start occuring hours after they leave the mental hospital. This book is very short and may seem like an average book, but it is full of twists and turns and you never know what is coming.