Back in April when we were in Florida, I spent several hours one afternoon at a tidal mudflat near the Honeymoon Island outside of Tampa. The tide was out and it was a good time to collect data on the intertidal snail Batillaria minima.
At the edge of the receding water outside the range of Batillaria minima, which lives quite close to the high tide mark, I saw a tube sticking vertically out of the mud.
I suspect it was the case of a polychaete worm. The worm itself was probably deep inside in a water-filled chamber waiting for the water to return. Either that or it was a drinking straw stuck in the mud. In the next picture my finger provides a scale.