Boogiepop

Boogiepop Phantom (ブギーポップは笑わない, Bugīpoppu wa Warawanai) is a Japanese anime television series produced by Madhouse Studios, based on the Boogiepop light novel series by Kouhei Kadono, particularly that of Boogiepop and Others and Boogiepop At Dawn. It aired for 12 episodes between January to March 2000.

Plot
Five years ago, a string of grisly murders shook the city to its core and now the rumors have begun once more. Boogiepop... Everyone knows that during the night, once meeting her and you never come back. People tell each other the stories and laugh: no one believes that she can possibly exist in this day and age. Still, strange things appear to be going on and the darkness is taking on many forms. Something is out there. Are you safe?