This is a variation of Jonny King's Kinky Muddler fly tied for Tarpon. The head is tied with Farrar's SF Blend and then trimmed. The result is a bulky 3-D head that pushes a lot of water. It is limited to 4" maximum length and uses lead wire wrapped on the hook shank to add a just a bit of weight. I believe this fly would work quite well on most saltwater predators that chase bait fish.
This fly has been used with much success in Cuba and the baby Tarpon fishery in Mexico. It will work on Tarpon anywhere.
It is sold in other places as the Snakehead Tarpon Fly, but credit for the origination of this pattern is usually attributed to Jonny King.