visual scratch _ crabs  baby scratch forwards transformer chirp
flare crabs  The crab scratch was created by QBert in 1995. He
saw DJ Excel do a twiddle scratch, which is a two-finger version
of the crab scratch. QBert expanded on the idea and created a
scratch that used all four fingers.  Crabs are much like a
multi-click flare, but the thumb holds the fader closed like a
spring while the other fingers click against it in sequence.
Sources: DJ Axel Foley, A Taxonomy of DJs  Wondering how this
works? Check out the description.