WOW!
And I thought I was the only one who noticed her.

For the most part, the characters you see in backgrounds are ether
plain to look at or have nothing to offer to the plot.
But once in a while you come across a character who looks so interesting,
that you want to skip the foreground and learn more about them.

and this diamond-type femalien is definitely something
too look at and wonder about. Here is her Biography.
Click: http://zim.wikia.com/wiki/Crystal