So, here we are to meet a Snakelock Anemone (Anemonia sulcata, or Anemonia viridis), sitting in a fluffy copse of Jania rubens.
Unlike some other actinias, anemonia prefers to hunt in a day time and sleeps at night. It hides it's body in cracks and chinks so only peppered with nematocysts (stinging cells) tentacles are let out waiting for a prey to come (that is the reason touching tentacles especially at the pinky ends is not recomended).