Deep ocean alien. Artwork of an alien life form adapted to survive on the seabed of a deep ocean. The life form resembles a tube worm as found on Earth. Tube worms secrete a substance which hardens to form a spiral tube. This becomes their home from which they feed by trapping plankton with tentacles. A planet or moon with liquid water and deep ocean geothermal activity, such as may exist on the Jovian moon Europa, could harbour such life forms. Sunlight cannot reach such depths hence energy and nutrients are derived from heat and minerals released by hydrothermal vents.