Tying a cone-head-rattler-streamer -- "DanBob's Diamondback."

"I caught one on the Poudre River the other day with this fly," he claims. It's as if the subtle vibrations of the rattle say to the trout, "Go ahead, I dare you." Sadly, the rattles tend to get waterlogged after a few casts, so this pattern is best used as an opportunistic sight-fishing fly.