Deep-Sea Octopus (Muusoctopus sp.)
Muusoctopus is a genus of octopus found worldwide in deep, cold waters. They are generally small to medium-sized, with smooth skin (unlike another commonly seen octopus at OOI sites, Graneledone boreopacifica, whose mantle has a bumpy or warty appearance). Muusoctopuses lack an ink sac, and females are known to brood their eggs in protected crevices without leaving to feed, sometimes for extremely long periods of time: months or even years!
These octopuses have been observed at both of the deepest OOI installation sites: Slope Base and Axial Base.
References:
https://en.wikipedia.org/wiki/Muusoctopus
https://daily.jstor.org/the-last-vigil-of-the-octopus-parent/