Eggstacy is a revolutionary new fly-tying material for egg-flies. Unlike standard egg-yarn, which involves spinning yarn, Eggstacy is built on a core which means you can simply tie it like a chenille. Eggstacy is the first material to be made from new “Next Generation” (NX-Gen Fiber). This material is a game-changer synthetic. NX-Gen Fibers are micro thin and designed to trap water, creating a slush-like texture when wet.