The Stimulator is often credited as being the brain child of Randall Kaufmann. Perhaps more marketing than pattern invention as the almost identical pattern called the Improved Sofa Pillow pre-dates the Stimulator as far as one can ascertain researching pattern books. There are others who claim the pattern was previously known as Frankenstein invented by Jim Slattery. Whoever deserves credit the Stimulator has become nothing short of a dry fly must have.
The reasons for its success are many. It imitates in various sizes and colors salmonflies, Skwala, caddis, hoppers, and it makes a great attractor as well. It floats so well it can be used in the dropper/hopper set up, it is easy to see, and let’s face it, it is just darn cool to look at. Sleek, curved, bright and bushy.
Aside from its aesthetics, the Stimulator is effective, easily seen by fish as well as fisherman it is a good rough water pattern, and in Royal color scheme a darn fine attractor. In its various colors it imitates, the Giant Salmonfly Hatch, the October Caddis, yellow and golden sallies, smaller salmonfly hatches, Olive Skwala hatch, smaller sizes are effective caddis, and caddis spinner, and emerger patterns, they can even be sunk to imitate drowned salmonfly and caddis patterns, awfully effective for nearly satiated trout.
When salmonflies and hoppers are both in the air and on the water simultaneously this pattern reaches its apex of effectiveness. Trout will take it for either insect with gluttony, one need be prepared with a gentle reflex and a delicate hand to prevent tippet snapping heartbreak.