[WestCoastOffensive]

Octopuses swim by expelling a jet of water from a contractile mantle, and aiming it via a muscular siphon.

Predation

Bottom-dwelling octopuses eat mainly crabs, polychaete worms, and other molluscs such as whelks and clams. Open-ocean octopuses eat mainly prawns, fish and other cephalopods. They usually inject their prey with a paralysing saliva before dismembering it into small pieces with their beaks.[30] Octopuses feed on shelled molluscs either by using force, or by drilling a hole in the shell, injecting a secretion into the hole, and then extracting the soft body of the mollusc.[31]

I guess you pay extra for this.