Sailor Heavy Metal Papillon (セーラーへヴィメタルパピヨン 'seeraa hevi metaru papiyon') is the final senshi of the Animamates who boasts sex appeal and beauty. She only appears in the manga (and just for a few pages at that) so very little is actually known about her.
Papillon is a hunter of souls, and when we see her she is in a graveyard at Zero Star Sagittarius surrounded by butterflies. Her job is to guard over the butterflies, which are in fact the last remnants of the Sailorsenshi who were casualties of Galaxia's campaign.
Her magical attacks are fire-based, unsurprising considering the old saying "like a moth to a flame." Her actual attack, which she never says out loud, is "Galactica Scales."
Sailor Heavy Metal Papillon almost kills Sailormoon, Sailorkakyuu, and Sailorchibichibi, but in the end Sailorchibimoon and the Sailor Quartet appear and destroy her before she can finish the job.
What the manga doesn't tell us is that Sailor Heavy Metal Papillon is originally from the planet Cocoon. It is easy to assume that she isn't the actual Sailorcocoon but in fact someone who was given Cocoon's powers by Galaxia - only those who weren't Sailorsenshi to begin with were called Animamates. Her real name is unknown, but the Materials Artbook gives some insight into her character; namely, she dances the samba and is easily moved to tears. It is also mentioned that she has a child, making her the only known senshi to be a parent in the present (as opposed to time-travelling kids from the future).