The curled octopus is a mollusc of the family Octopodidae and has no particular preferences as regards substrate, although it appears more widespread in areas with sandy or muddy bottoms, where it makes its lair at the base of isolated rocks or large shells, bottles, vases etc. The animal leaves its shelter at night to seek food. It measures up to 40-45 cm in length, arms included. Males can be as small as half the size of females and their size tends to increase as the water gets colder. The curled octopus’s mantle is covered with numerous little granulations, interspersed with larger warts, and tends to be longer and broader than the head. Its normal colouring is yellow verging on light brown, with reddish patches, but it can change colour instantly, becoming lighter or darker according to mood and the surrounding environment. Two strands of skin are present just above the large eyes, which have prompted the animal’s alternative name of “horned octopus”. Each of the eight arms has a single row of suckers. In the male, the third arm on the right is shorter than the others and the tip includes a copulatory organ.