User blog comment:Toyoguchi/My first ever RWBY wiki Blog/@comment-4010415-20150603192242

The "thingy" attached to Blake's weapon is a ribbon. And, to expand on what Live said, basically it's a katana with a pistol for the handle, and its sheath is a cleaver that has a handle in the blunt side, so she can dual wield. The blade of her katana folds up to turn into a sickle, and she uses the ribbon to swing it around, like a kusarigama, which is a chain-sickle. Also, toward the end of her katana, it's bladed on both sides, so that when it folds up, it's bladed all around.