As several savvy readers guessed, the photo in the previous post was of a polychaete annelid (worm) taken from the area around deep-sea hydrothermal vents. Here are a few other species (I don’t have the Latin binomials), and you can see more pictures here.
They’re visions from a nightmare, but they also inspired in me the sentiment expressed by Richard in the previous thread: “Isn’t evolution wonderful!”
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.