The swimming anemone (Aquaperogo lophiurus) is a species of cnidarian existing 200 million years in the future. It is about 90 centimeters long.

Unlike its ancestors, which had a sedentary lifestyle attaching themselves to rocky surfaces, the swimming anemone has, as its name suggests, developed a free-swimming lifestyle. Its 'foot' has evolved into a fluked tail which can propel it forward. Much like ordinary anemones, it has a rozette of tentacles surrounding its mouth. As in any cnidarian, these tentacles are covered in cnidoctyes - microscopic harpoon-like projectiles loaded with neurotoxin. While swimming, the creature retracts the tentacles to improve its streamlining. The creature senses its surroundings through smell and vibrations. Due to its boneless structure, it can bend and squeeze itself into narrow gaps to get at hidden prey. This also allows the creature to eat very large prey, although prey that is too large can make it vulnerable to predators as it gets sluggish. After digestion, remains such as teeth and bone are regurgitated.