Slide a large black bead onto the shank as far as it will go before being stopped by the returned eye on the OPST Intruder Shank. Tie in a short length of doubled OPST lazar line or other thick mono material, with the end of the loop about 3/8 back from the bead. Wrap thread back about 1/4" over this, leaving about 1/8" of mono loop.
Tie in the Senyo Aqua Veil Chenille in front of the mono loop. Don't crowd the loop- leave enough space so you can force the loop up with your finger. Wrap the chenille forward to the bead, whip finish, and tie off.
Tie down your thread in front of the bead. Select two OPST saddle hackles. Strip the barbs off a quarter inch or so of stem, and tie the stems in right up against the bead at a rough V shape and angling slightly upwards, trying to put some angular distance between the hackles. On this particular fly the hackles extend back about 3 inches from the bead. Make a dubbing loop that you will use in a few minutes.
Prepare a composite loop using ice dub as the base, or "velcro". Take a clump of ice dub, and, clamping one end of the fibers, pull out the loose ends, clamp those as well, and repeat the process until you get a more consistent length of fibers. Some packs of ice dub vary in length, but do your best to get consistent one inch or so long fibers. Lay these down in a thin but thorough layer along about a 4 inch straight line. The line represents the thread of your dubbing loop, and will be the dividing line as we prepare the materials in the next step.
Select 4-5 legs and cut them in half so they are about 3 inches long. I alternate the colors on these hot-tipped sili legs and place them on the dubbing, with the butts of the legs not longer than the width of the dubbing- about 1/2" max. But don't make the butts too short, because the most difficult part of this fly is keeping the rubber legs in place when you place the whole mess in the dubbing loop. These will be wrapped first, and that is important because they are easier to place in the dubbing loop if they are at the top.
Next, add 3 inch lengths of 3 grizzly magnum flashabou and place them 50/50 over the line. Add about 12-15 strands or enough to cover about one inch of your assembly.
Using a toothbrush, brush about the same amount of lady amherst fibers to separate the fibers. Then lay them down the same way as the rubber legs- you can get away with shorter butts here as this material is easier to handle in a dubbing loop.
Finally, add about 2 inch strands of angel hair, about 3/4 inch worth, 50/50 on the line. This material will serve as the head of the fly.
Place another layer of dubbing over the center of the whole assembly, making a sandwich between the two layers. Compress the materials as much as possible, as the next step will be easier if the materials are more stuck together. Remember, the ice dub is your velcro.
Now, with your non-dominant hand holding your OPST dubbing spinner in the dubbing loop, carefully pick up the entire assembly and put it in the dubbing loop, clamping the rubber legs between your thumb, index and middle fingers. The rest of the materials should come along without much trouble, but it's critical you secure the rubber legs in the loop. Make a couple of spins with your dubbing spinner to tighten it up. When the situation is stable, and with one hand still on the dubbing spinner to keep tension, spread out the materials as evenly as you can with a whip finisher or other pointed object. Try to separate clumps and fill in empty spaces. Cut or manually straighten out any long ends or butts.
Spin the loop aggressively. As it slows down, use a toothbrush to guide some of the fibers to prevent tangling. Spin the loop again, and then keep tension. Pick out the loop, trying to release trapped fibers. Then take a toothbrush and give them entire loop a thorough brushing. Try to find a "neutral point", where the loop tends to stay put, and hold the loop in place there for the next step.
With a bowl of water, use your hands to wet and compress the loop, parting it into the shape of a hackle. Pull gently on the fibers as you compress them. The wetter you get it, the easier it will be to wrap. Now wrap the hackle forward to the eye, palmering as you go. Whip finish. Brush the fly backwards and forwards, and wait for it to dry and see what you have created!