Octopuses are extraordinarily versatile. From walking across the seabed on their eight arms to jetting through the water, manipulating tools and squeezing through unimaginably tight spaces, the flexibility of octopuses almost defies belief. "Octopuses can change their body shape to squeeze through tiny holes, almost like water flowing through a gap, so their size doesn't always limit where they can go," says Wenci Xin from the National University of Singapore.