Gary LaFontaine designed the Sparkle Pupa after watching emerging caddis carry a glistening sheath of trapped air toward the surface. The fly recreates that look with a loose halo of Antron (sparkle) yarn over a dubbed body. Underwater, the fibers catch light and read like the gas bubble a real pupa uses to rise. That shimmer is the whole point of the pattern.
Tie or buy it in sizes 12-18, in olive, tan, or amber to match the caddis on your water. Tan and olive cover most hatches. It fishes best in water from 50-65F (and works from 46-70F), in clear or stained water at low to normal flow.
Fish it through and just before a caddis hatch, when you see fish flashing under the surface but not eating dries yet. Swing it on a tight line through the back of a run so it rises like a real emerger, or drift it dead under an indicator and let it lift at the end of the drift. Most takes come on that rise, and they come hard. Trout are the target.