Vulcanoctopus hydrothermalis, also known as the vent octopus, is a small benthic octopus endemic to hydrothermal vents. It is the only known species of the genus Vulcanoctopus. This vent octopus is endemic to the hydrothermal vent habitat that is located in the East Pacific Rise.

An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.