Really just the front half of an Intruder, when I want something a little more subtle for low and/or clear water or small streams.
Tube- Various length copper tubes, depending on desired weight/sink rate.
Body- Micro braid
Thorax- Arctic fox, sun in a dubbing loop and brushed out
First Hackle- Ostrich spun in a dubbing loop. I like to mix two colors, olive/orange, black/blue/, black/purple, pink/white.
Second hackle- schlappen
Third hackle- dyed Guinea Hen
A cone head or monster cone can be used to increase sink rate and/or increase the turbulence around the fly, causing more flutter and movement of the feathers.