Mount the heavy #6 curved hook, start black thread, and wrap to the bend.
Tie in a marabou tail one shank length long at the bend.
Bind a 1/4in-wide foam strip in at the bend (a dab of superglue holds it), leaving the long end trailing rearward.
Tie in the purple Estaz chenille at the bend.
Wrap the Estaz forward in touching turns to the 85% mark and tie off, leaving room behind the eye.
Pull the foam strip forward over the top of the Estaz and bind it with loose wraps that you gradually tighten (so you don't cut the foam), forming a buoyant head/back.
Trim the foam head short, whip finish, and cement.