Checked it. Bringing back B.B.

[url=http://fc04.deviantart.net/fs70/i/2011/067/0/4/arakune_blazblue_by_tamuchiroid-d3b6r2f.jpg]Black Beast[/url] - A relatively new species of Grimm. They lack any form of physical shape, adapting to whatever best suits the situation. More akin to sentient liquid. The only consistent feature is it's plain round mask, which vanishes and surfaces with little to no cadence. Capable of producing potentially infinite amounts of bone-like appendages in various shapes and functions, from cutting blades to thick shields. They lack any consistent appearance, size, shape, or even population number. While spotted in various locations around remnant, they are often found alone, within the city, and only once in a while. It has been suggested that each sighting is the same creature, due to it's activities and appearance. So far has yet to actually attacked or caused any sort of incident, but whether it is out of benign interest or simply because no one has lived to witness it's hostility, it is so far unknown.