Lay a thread base from the eye back to just inside the barb and trim the tag.
Tie in red medium cactus chenille just at the bend, take a few wraps to form an egg-sac/gills suggestion, and trim.
Tie in the crustacean eyes on top with figure-eight wraps so they splay outward (optional).
Clean and stack a tan clump and a chartreuse clump of pseudo hair, blend them, and tie them in on top of the eyes with tan on the bottom and chartreuse up, about a shank-length long; mark three brown bars with a Sharpie.
Tie in pink medium Palmer chenille and wrap 2-3 turns over the tail base, then a few more just behind, and secure.
Tie in medium Krystal hackle (dot it with black for barring), palmer five or six turns, tie off, sweep the fibres back and brush them out.
Cut the EP 3D fibers into 2-inch sections and figure-eight them in a body-brush style, alternating pink and chartreuse clumps and holding tied clumps back with hackle pliers so each new clump seats close.
Advance to the eye, tie in the bead-chain or lead eyes on top with figure-eight wraps, build a thread head and whip finish.
Trim and shape the fibre body into a crab profile and coat the head/wraps with Loon UV Thin, then cure.