An octopus brain as a single discrete organ is somewhat misleading. The bulk of their neurons actually cluster in their arms, which possess a form of short-term memory and can clutch and grasp even after being surgically removed. This distributed neural intelligence is highly unusual, and it blurs the standard boundaries between mind and body. The arms of an octopus are not only appendages controlled by a central command center; they are also semi-autonomous units that can explore, move, perceive and remember.