Hot spot / thorax Purple (or hot-spot orange) dubbing or thread build (small pinch)
Collar Natural gray (or dyed) CDC, wound as a soft collar (1 feather)
How to tie it
Slide the slotted tungsten bead onto the jig hook, slot forward, seat behind the eye, and start the thread.
At the bend, tie in a small bunch of speckled Coq de Leon fibers as a tail about a shank length long.
Tie in the copper wire; wind a slim pheasant-tail (or purple Ice Dub) abdomen forward to about the 60% point.
Rib the abdomen with the copper wire in 4-5 open turns for flash and durability and tie off.
Build a short purple hot-spot thorax/collar zone just behind the bead (the colored 'hot spot' is the trigger).
Wind one turn or two of CDC as a soft, mobile collar behind the bead, sweep fibers back, tie off, and whip finish. The CDC breathes and the jig hook rides point-up for fewer snags.