is a 2010 anime series directed by Takahiro Omori and produced by Brain's Base.

The episodes are adapted from the light novels of the same name, written by Ryōgo Narita and illustrated by Suzuhito Yasuda.

[1] The series follows several people in Ikebukuro: Celty Sturluson, a dullahan working as an underground courier while looking for her lost head; an internet-based anonymous gang called the Dollars; and the chaos that unfolds around the most dangerous people in the city.

[2][3] Crunchyroll simulcasts the anime within 24 hours of its Japanese premiere to its members, becoming a free-for-all a week later.

[8] The anime was also broadcast in the United States on Cartoon Network's Adult Swim programming block from June 26 to December 18, 2011.