Throwing in tail in freezer after cooking it right?It is a system for sealing holes in the shells from the inside, and it is like purple epoxy. I drip some on the ground when I am cleaning them, just to see it and remember, and it lasts months. Very strong stuff. If you (or a sheepshead) punctured a hole in the shell, this would ooze out and seal the hole from the saltwater, rather quickly. I used to work at a place that processed live lobster, and have seen the glue in action. Try it next time you have a live bug, but do it somewhere F&G does not suspect you of hooking it! It seals in minutes. I work in an OR now, and they use a product called Dermabond by J&J that is a skin glue/sealant, use in sealing surgical wounds. I swear the idea for this had to come from lobsters. Looks exactly the same! Never really had black stuff come out, I rinse mine in fresh water and dry before wrapping and freezing.