Keith Fulsher developed the Thundercreek series in the early 70s. Straight eye streamer hook, bucktail in the color of certain species of baitfish, tied in by the hair butts, extending over the hook eye and folded back. Add eyes and some varnish or resin on the head and you’re done.
I first learned about them in the 80 and have fished them ever since. Great flies!