To many of its neighbors, Amphioctopus marginatus, an octopus found in the waters around Indonesia, is just a mouthful of sashimi. To shake that fate, it acts like a coconut. 

Octopods generally either slither or swim by jet propulsion. As a graduate student in Indonesia in 2000, Christine Huffard (now senior research technician at California's Monterey Bay Aquarium Research Institute) was amazed to see A. marginatus, also known as the coconut octopus, wrap up six of its arms into a ball and "run" backward on the other two. To predators, it doesn't look like an octopus; it looks like a walking coconut. 

But it's hard to run from fish that bury themselves in the sand, with only their eyes sticking out. ("It's as if whenever you walked down the driveway to get the mail, at any point you might step on the mouth of a mountain lion," says Huffard.) So A. marginatus carries around a coconut shell that it can hop into in extremis. Some carry two, closing them around themselves when necessary.

Does this make the coconut octopus the only tool-using invertebrate? "It's probably the closest we'll get to meeting an intelligent alien," CUNY philosophy professor Peter Godfrey-Smith told the New Yorker. It comes down to whether A. marginatus carries the shells for future use, which might indicate foresight, or whether they're constant shelter, like a hermit crab's shell. 

Oh yes, and when all else fails, the coconut octopus glows blue. As one does.