Note: This recipe has not been verified against a documented source, or disagrees with one. Treat the materials and steps as unconfirmed.
Classic Recipe
Hook Saltwater hook, 2-6
Thread Tan/orange 6/0
Materials
Body EP Fibers or craft fur (shrimp/crab-like)
Eyes Lead dumbbell or bead chain (1 pair)
Legs Sili legs (2-3 pairs)
Weight Lead to ride hook-up (underneath)
Weed guard Heavy mono (1)
How to tie it
Mount hook, tie in dumbbell or bead chain eyes underneath the shank so the fly rides hook-point-up.
Build the body with EP Fibers or craft fur in clumps, shaping something between a shrimp and a crab. Flats prey is often ambiguous, and that ambiguity works for you.
Add 2-3 pairs of Sili legs along the sides, the subtle leg movement at rest is a major trigger.
Tie in a heavy mono weed guard from the head, looping down past the hook point.
Trim the body to shape, whip finish.
Other versions
4 more in the app: Sight Cast Fishing Company, Global FlyFisher (McFly Angler), Bill Morrison, McFly Angler.