This is so bizarre.
I once saw an entire PBS program on these guys. This video is not as impressive as some of the other examples I saw. They had one of an octopus going through one of those distilling rigs where there is a big glass sphere at one end, and a glass tube at the other end that is really quite small and goes around and around like a spiral staircase. kind of like an old fashioned still. The octopus started out in the sphere and squeezed around the tube and out the other end like a distillate of octopus. I wish I could find a video of that one. They have no bones, cartilage maybe, but no bones.
There was a scientist in the program who told of a lab that he once worked at where an octopus was on one side of the room and an tank of crabs on the other. The crabs kept disappearing. The staff would come in at sunrise to find all the crabs gone and bits of crab shell scattered all over. They had no idea what was happening to them except, obviously, something was eating them. They set up a "nanny cam" sort of thing one night and sure enough it was the octopus. It would heave itself out of the water in it's aquarium, hop (splat?) down to the floor and crawl into the crabs tank, chow down and then mosey on back to it's own aquarium. I think they had to put a top on the octopus's tank.