Well, to describe it, it's about a girl named Lucy (a Diclonius). She possesses telekinetic powers called "Vectors" (they resemble long arms), which can hold and even slice stuff and are invisible to the naked eye (other Diclonii can sense them). She has been ostracized by humanity because of her unusual appearance, most notably her horns (they look like cat ears) and pink hair. Now she wants revenge against humanity.
It's a hit series here in the states, as well as overseas (In Japan, it was a flop since it aired in the wee early morning hours on a satellite channel). It's also very not for the faint of heart (very violent as well as having a good amount of nudity on top of having transgressive subject matter).
I have a box set of it and watched it myself
You can watch it
here.