This is a small crayfish pattern. It's simple and doesn't use any expensive materials, so I don't feel too agitated when I snag and lose one on a rocky bottom (which will happen occasionally when you fish this correctly). The dumbell eyes will allow the hook point to ride upwards, a la the clouser minnow.
Hook: 2XL, size 6, slightly humped (i.e., a stonefly nymph hook)
Thread: 6/0 rust or brown
Eyes/weight: Black dumbell eyes, sized to pattern
Claws: Hackle tips
Body: Brown or rust chenille
Legs: Palmered hackle
I use the slightly humped hook because it gives a more natural presentation. Instead of the fly laying parallel to the bottom, the position of the eyes (which are anatomically on the wrong end) and the curvature of the hook give the appearance of raised claws and a defensive posture.