Umbridge's Quill

[Kelly]

No: HPFGUIDX 170517

Like many of you, I've been re-reading the books and started wondering
about the blood-letting quill of Delores Umbridge.  I saw in an
interview that Umbridge would make a re-appearance in the last book
and that there would be opportunity for her to receive more bad
treatment from the author.  What do we know about this quill?  What
happened to it and what was it created for (doesn't it seem like
something someone would use for a dark contract)?  Could this be of
importance in the final book?  

When I was re-reading for some reason this "dark object" started to
make me wonder.  I know objects often make a re-appearance.  Does
anyone have any thoughts on this?

The main thought I have is that it may have been the tool by which the
dark mark tattoos were created.