Elfen Lied was the first genuinely disturbing anime I watched, and yet it's macabre in such a way that it engrosses the viewer. The themes in the series are really powerful as well, and I prop the staff behind it for packing a consistent amount of tantalizing material in a 12-episode span. Don't know if I'd call it a masterpiece, but the thought is definitely there.

While it was pretty short, the duration felt just about right to me... To continue the series, or expand on any episode to elongate the length would feel unnatural.