Our oceans are home to some of the most unbelievably strange and wonderful creatures on the planet. The mantis shrimp, which grows to an average of only 10 centimeters long, has a punch that can shatter glass. The Portuguese man 'o war, usually thought of as a jellyfish, is actually a colony of codependent creatures called zooids. When attacked, the deep-sea Atolla jellyfish can emit a flashing blue light so bright it can be seen from 300 feet away. With traits like these, it's no wonder that an adjective often used to describe these creatures is "alien." The descriptor is fair: our oceans practically are another universe. When the deepest (known) point in the ocean's deepest part, the Mariana Trench, is further than Mount Everest is tall, it's no surprise that only a fraction of the world below us has been explored.

But some of the most alien creatures of all, often going overlooked, are the octopuses. Yes, octopuses. The word comes from the Greek "oktopous," meaning eight-footed, while the "-i" suffix often attached to the word is a Latin ending. While common usage of the spelling "octopi" has made it acceptable, it is still technically incorrect.

Octopuses may seem plain compared to a lightweight boxing champ shrimp or a rave party jellyfish, but they are actually extremely complex, fascinating creatures. With remarkable intelligence, formidable strength, and incredible survival skills, they are well worth studying.

The intelligence of octopuses is something that often surprises people, but they should not be underestimated. There are stories everywhere about the ability of octopuses to solve problems, remember people's faces after years apart, and escape enclosures like ocean-dwelling Houdinis. The best stories are from zoos, where these cephalopods will do incredible and ridiculous things for fun or food, squeezing their huge bodies through tiny cracks and dragging themselves down hallways to cause mischief or steal a snack from other tanks.

Octopuses' strength is not to be dismissed either. With hundreds of powerful suckers lining their eight arms, which are almost entirely muscle, all the way down to where they meet at a punishing beak, a large octopus can subdue sharks and break Plexiglass. Not only are these arms strong, research suggests that they may have minds of their own: they can move and react to stimuli without signals from the brain.

Octopuses also have an unnecessary amount of crazy defense mechanisms. With ink sacs, venom, speed, intelligence, and strength, you'd think they'd be fine, but they're also masters of camouflage. With the ability to change the color and texture of their skin, they can blend seamlessly into almost any environment. With this skill, they hardly ever need to fight or flee. Still, when they are attacked, they're clearly more than prepared.

Even this little guy.

Suggested reading, and the source of a lot of this information: The Soul of an Octopus, by Sy Montgomery.