Kelly Galloup's Sex Dungeon was recently made more family friendly and renamed "Dungeon". This fly is an absolute requirement in any big streamer box. The head is packed with deer hair. That deer hair pushes water and the dumbbell eyes help it sink.
Every material used on this fly (and every one of Kelly's flies) was carefully selected to enhance movement and allure to brown trout.
Best fished on a sinking or full sink fly line.
Cast, strip, jerk, and hold on.