This glue gun variation of the Double Egg Sperm Fly was tied by regular contributing fly tyer Scott Howell. The original version was tied with chenille "eggs" (which see). You can see more of Scott Howell's flies at The Flies of Scott Howell. See his notes about this fly below.
Scotty's Notes: Originated in the mid-1960's for Salmon and Steelhead in Alaska, this popular pattern is tied in many florescent colors, both weighted and unweighted, and is also known as the Two-Egg Sperm Fly.