I do wonder if someone should make a personal tag for the darker wriggle in this image, she seems to be rising in popularity herself along with the princess.

She should definitely be tagged if she has a name.

EDIT: apparently from http://nameya.s269.xrea.com/princess_wriggle/story.html, she's just been called kuroi wriggle / kurohime. So it's really nothing more than Dark Wriggle in the end. Kind of disappointing somehow.