Michael McGovney has spent a lot of time chasing large bonefish in very shallow water. Super spooky and very picky fish. Standard bonefish flies just don’t do the trick. Studying the flats he fished, McGovney noticed lots of crabs so next step was to try the typical permit crab but the problem with those he found out very quickly is they are like throwing rocks at them. Every cast the fly would hit the water and spook every fish within 20 feet of it. So McGovney went back to the vise and dug thru materials until he came up with the simple crab. It lands soft, hook up and when wet looks just like a real crab. The material even holds some air bubbles.
The key to it is to fish it slow. Once a fish has spotted it leave it which makes the fish think the crab is hiding. Fish will run right up to it and grab it