Kalketrappes

Rev. Skeat writes: "Kalketrappes, calthrops or caltrops; defined by Webster as 'an instrument with four iron points [fastened to a ball] so disposed that, three of them being on the ground, the other projects upward.'" (258) Now compare Go Go Yubari, using her morning star chain adaptation of this medieval torture device before Uma slices her:

Shown below on either side of her boss O-Ren Ishii, Go Go appears to have two different weapons:

Now listen to the music that starts the scene.