Sharpie Dressed Caddis
Hook - Tiemco/TMC Model 2487 (Size 10) Caddis Pupa Hook (Thanks John/CreationBear)
Underbody - UNI-Stretch (Orange)
Abdomen - Fly Tying Dungeon Baby Legs Alive stretchable floss (Creamy Yellow)
Thread - 8/0 UNI-Thread (Orange)
Throrax - Awesome 'Possom Nymph Dubbing (Rich Brown)
Hackle - Honey Dun Hen Neck Hackle (Natural)
After the fly was finished, the back of the fly was colored with a couple Sharpie permanent markers. First brown was run down the back (top half only). Once that had dried, small dots were made with a black Sharpie marker to add additional segmentation. Obviously the color variation could be infinite. Have fun.
Here is a photo of the same fly, as viewed from the bottom.