Mount a short wet hook and start orange or chartreuse thread behind the eye; run a thread base back to the bend.
Cut a pair of short foam cylinders (or a single foam booby cord) and lash them across the TOP of the shank at the very rear, right at the bend, with figure-eight wraps so they sit like booby eyes at the tail; add a drop of glue. This foam at the back is what floats the fly butt-up.
Tie in a length of Blob fritz (straggle/blob chenille) just ahead of the foam.
Wind the fritz forward in touching turns, stroking the long fibers back after each wrap to keep them free, building a dense, translucent blob body up the shank.
Stop one eye-length behind the eye, tie off the fritz, and trim the surplus.
Sweep the fibers back, build a small thread head, whip finish, and add a drop of cement.
Pick out the blob fibers with a dubbing needle so the whole body bristles.