The female octopus dies shortly her eggs hatch.
Picture from ACurious
Many scientists believe that the female octopus dies shortly after mating. She will lay her eggs and live long enough to guard them until they hatch. The female octopus will gently blow water currents over them so they growing fetuses will get enough oxygen to survive. Once the eggs hatch, the babies will begin to rise towards the upper waters of the sea as the mother dies.