Head Closed-cell foam (yellow or hi-vis) (one strip)
Thorax Same dubbing or peacock herl (as needed)
How to tie it
Start thread mid-shank and dub a slim tapered abdomen from the bend forward over the rear two-thirds of the hook.
Stack a small clump of elk hair and tie it in as a down wing, tips reaching just past the bend. The elk hair breaks up the silhouette and adds flotation.
Lay a strip of closed-cell foam over the top of the thorax area, tip pointing forward, and bind it down at the front.
Dub a short thorax (or two turns of peacock herl) up to the eye, then pull the foam back over the top to form a raised 'balloon' head and lock it with thread.
Whip finish under the foam head. The foam balloon keeps the fly riding high and visible in rough water.