Cone Copper or black cone (1, mounted reversed at the bend)
Claws/antennae Brown permanent marker (splayed hackle tips or rubber legs)
Body Crawfish orange-brown (dubbing brush or chenille)
Rib Copper thorax stripe (medium wire)
Shell/back Mottled brown pectoral fins (thin skin or scud back)
Legs Brown silly legs nymph size (palmered soft hackle)
How to tie it
Mount the hook and slide a cone onto the shank reversed so it sits toward the bend, this weights the tail so the fly darts backward like a fleeing cray.
At the bend, tie in two splayed hackle tips or rubber strands for defensive claws, flared wide.
Bind in the copper wire and a strip of thin skin for the shell back.
Dub or wrap a fat tapered body forward to just behind the eye.
Palmer a soft hackle through the body for legs, then bind at the front.
Pull the thin skin shell over the back and rib the copper wire forward in 5-6 turns over it to lock everything and segment; bind and snip.
Build a head, whip finish, and stroke the claws so they flare in the defensive posture.