Thread Black (olive works equally well) 8/0 (6/0 also fine)
Materials
Tungsten bead Gold or black bead (1, 2.4 mm)
Wire underbody Any wire (Medium, a 6-8 inch piece)
Dubbing blend: Montana Fly Co. Sculpin/Generation X (olive, with fine rubber fibers) + olive Hare's Ear-type dubbing, equal parts, plus a pinch of holographic ice dub Olive (or a chartreuse/olive two-tone version) (Enough for a fat body)
How to tie it
Slide a 2.4 mm tungsten bead onto a #16 curved caddis hook and mount the hook in heavy jaws so the midpoint of the bend is exposed and the hook cannot shift.
Anchor a 6-8 inch piece of medium wire against the vise with your thumb and wrap it up the shank in tight touching turns from the bend to the bead, sneaking the last wrap or two right up under the bead.
Wedge the wire at the bead, break it off by hand, then push the wire wraps forward to jam the bead tight and open up one wrap's worth of space at the rear; break off the back end of the wire with fingers or pliers.
Start the thread in that gap behind the wire and lock the wire underbody down.
Dub the olive blend on heavily and tightly (it has fine rubber strands in it, so keep it packed) and wrap forward to roughly the 50% point of the shank, piling it on thick.
Continue dubbing right up behind the bead, stroke the fibers back, sneak the thread in tight behind the bead, and tie off with a few wraps; make sure that final thread is right against the bead so the dubbing can't be pulled free.
Whip finish and trim the thread.
Brush the body out roughly with a piece of Velcro, sweeping the fibers back to make the fly buggy, then trim the longest rubber strands so they aren't excessive.