It commonly preys upon shrimp, crabs, and clams, and displays unusual behavior including bipedal and quadrupedal walking as well as tool use (gathering coconut shells and seashells and using these for shelter).

The octopus displays a typical color pattern with dark ramified lines similar to veins, usually with a yellow siphon.

[2] In March 2005, researchers at the University of California, Berkeley, published an article in Science in which A. marginatus was reported to show bipedal locomotion, or "stilt-walking".

[6][7] In 2009, researchers from the Melbourne Museum in Australia observed the coconut octopus uses tools for concealment and defense by gathering available debris to create a shelter.

They were then carried up to 20 meters (66 ft) and arranged around the body of the octopus to form a spherical hiding place similar to a clam-shell.