Hello everyone, it's my first post here.
Recently around the Gulf at Muscat, Oman, I found this tube-like structure bind strongly to a rock after some digging with my hands under the water on a remote small beach (no signs of previous visits there.) There's no sand on that shore, instead a coarse-sand-like nature of very small shell and rock fragments. The start of this tubular structure is very narrow, and its radius increases as it appears to curl in a life-like form of some organism. Unfortunately the top appears missing when I found it.