The name of a Japanese manga and anime series, itself an abbreviation of "Mukuro naru hoshi tamataru ko". Author Mohiro Kitou /(Kitoh).
Especially ignore Sidelabel's definition as he has shown that he doesn't know what he is talking about.
Its quite a realistic, shocking, and thoughtful series about power in the hands of adolescents.
Its also a very misleading series, what appears to be a cute Shoujo story soon turns into a pitch black investigation of the human psyche.

(1) Shadow Star
(2) In Sidelabel's opinion, a pile of shit.
(3) Suicidal schoolgirls and freaky dragon things.
(4) 13 episode OVA fansubbed by The-Triad and AnimeONE
(5) Tentacle raping (Source - OrochiTux)