ROLZ!!!! Ringu has already been said, but yeah, I saw It when it first was released (The Jap version) and I found my self looking at every creek to check it wasnt Sadako, plus I didnt trust me TV for a while.
Supposedly the scariest film ever is The exorsist, But I would not watch something like that so I dont know.
Also, Audition was scary, ANYONE SEEN AUDITION ????? About the Crazy Japanese woman, who is very scary
