Start the thread leaving a bare section of shank behind the eye. The helmet has to slide on there later. Lay a base back to the bend.
Select two soft, fluffy marabou plumes (not stiff blood quill), line up the tips and tie in a tail about one shank-length long; bind the stems down the shank.
At the tail tie in the crosscut rabbit strip hide-up with the hair sweeping rearward, and tie in the UV pearl polar chenille alongside it.
Wrap the rabbit and polar chenille forward together, folding the chenille strands back with each turn so the flash blends through the fur. Stop at the bare front section and bind the hide down hard.
Tie one pheasant rump feather flat along each side as pectoral fins, using plenty of tight turns; keep the tie-down area slim.
Test-fit the sculpin helmet over the head to make sure it seats, then whip finish and cut the thread.
Coat the thread wraps with marine Goop and push the helmet on with the heavier side down so the fly rides hook-point-up; let it set. The Goop fills the voids and no thread dam is needed.
Glue the eyes into the helmet recesses (Goop or UV resin) and clear the hook eye with a bodkin or feather stem.