Schlappen or saddle hackle (optional) Purple / black schlappen (1 feather)
How to tie it
Lay a straight pin (or short length of stiff wire) along the top of the hook shank so it projects past the eye, then thread the bead onto the pin so it sits out in front of the eye; lash the pin firmly to the shank with tight thread wraps and cement. This is what makes the leech ride level and 'balanced'.
Start the thread and wrap back to the bend.
Tie in a purple marabou tail about one shank-length long, kept slim.
Add a few strands of purple/UV flash along the tail, the same length.
Twist purple UV ice dub onto the thread and wrap a buggy body forward from the bend to just behind the bead.
If desired, palmer a soft hackle through the front third for extra movement and tie off, sweeping the fibers back.
Build a small collar behind the bead, whip finish and cement.