Researchers in Australia found that female octopuses use their arms to throw silt, algae and shells at unwanted male mates when they feel harassed.
"My Octopus Teacher" directors speak about the movie and the unique octopus living in a kelp forest off the coast of South Africa.
The dramatic footage sees a crab take on the deadly blue-ringed octopus—and survive.
"If she is dreaming, this is a dramatic moment. You could almost narrate the body changes and narrate the dream," the scientist said.
The material could make great military camouflage devices.