This fly was originally designed by Pennsylvania resident Walt Young. If I am not mistaken it was orginally tied to imitate cranefly larva. I have had a lot of success with this fly before caddis hatches so the fish may take it as caddis larva/pupa. I also think it would be a good scud imitation in smaller sizes. What ever the fish take it for is immaterial because they take it often enough that it is a go to fly for me.
Hook - 2x long nymph hook (10-16)
Underbody - .015 lead wire
Body - Hare’s Ear dubbing (I use Hareline Plus #1)
Thread - Tan 6/0
This fish was caught on a Walt's Worm that was tied by my son, who was five at the time.