I found this plastic tube hanging in the seawater from a pier in the haven of Taranto, Ionian sea, southern Italy. I'm wondering what is the whitish jelly in the lowest part of the photo next to the yellow Botrylloides violaceus. It didn't seem to come off easily (I didn't insist much though) and it didn't have any macroscopic reaction when touched (no contraction or similar).
The photo was taken on the first days of January. The water was shallow in that point (no more than 2m deep) but close to deeper water, as expected from a haven, and rather polluted.