This may be the tiniest sea monster, a hydrothermal worm, a deep sea creature, almost as small as bacterium found near hydrothermal vents in the ocean. Here is the “worm from hell” viewed close up with an electron-microscope. Click on the image to see a larger view.
Hydrothermal Worm Viewed Under An Electron Microscope
If I remember rightly, they thrive in the sulphurouos effusion and exist in conditions under which normal life supposedly cannot exist. Amazing – and ugly too!