It's International Cephalopod Awareness Days, a five-day celebration of more than 700 sea creatures that make up this class of animals. The festivities kicked off Oct. 8, a date "chosen as an auspicious occasion for appreciating animals with a combination of 8 or 10 appendages," explained the Cephalopod Days Tumblr. "Octopus have eight arms while squid and cuttlefish have eight arms and two tentacles. So the eighth day of the tenth month seemed like the best choice. But cephalopods are so awesome, four more days were added to the celebration." We couldn't agree more. Here are 13 reasons these crafty creatures rock. Above: Thermo Dynamics Octopuses living in freezing waters can customize proteins called potassium channels that open when nerve cells fire, allowing ions through and helping transmit electrical signals across the nervous system. As it gets colder, the channels should shut more slowly, preventing nerve cells from firing again and ultimately bringing movement to a halt. Amino acid changes in the potassium channels of polar octopuses keep their nervous systems working at temperatures that would shut temperate-dwelling creatures down. Image: Common octopus. (Beckmannjan/Wikimedia Commons)

Brains and Brawn Cephalopods have the biggest noggins among invertebrates. Squid come equipped with big optic lobes, which help them hone in on prey, for example. Plus, these tentancled swimmers have the largest nerve cells of any animals. Squid are also the speediest marine invertebrates, getting up to more than 25 mph using jet propulsion. After water goes into the squid's body, it squeezes it out with its strong muscles and propels itself. Octopuses, which have nine brains and can be trained to do various tasks, are 90 percent muscle. Image: Giant Pacific octopus. (Magnus Manske/Wikimedia Commons)

Masters of Disguise Rather than just using camouflage to evade predators, the Indonesian mimic octopus can shape itself after various toxic creatures. These masters of disguise can also outswim their adversaries by growing larger arms. Other cephalopods, like the cuttlefish featured in the video below, activate color sacs known as chromatophores to flash different colors. Image: Blue-ringed octopus. (Wikimedia Commons) Video: Cuttlefish (NOVA/PBS)

Octopi DIY Some octopuses from Indonesia use repurposed coconut shells as homes. Others use shells to protect themselves. Image: Octopus marginatus inside two shells. (Nick Hobgood/Wikimedia Commons)

Multitasking Different regions of the octopus brain can control different parts of its body, giving it great physical flexibility. Image: Roy Winkelman/University of South Florida

Predicting the Future, Sometimes Paul the Octopus predicted the results of eight consecutive games correctly during the FIFA 2010 World Cup, including the final. Paul passed away in October 2010 at 2.5 years old. Tear. Image: News footage screengrab of Paul picking Spain over Holland in the World Cup final. (Voice of America News/Wikimedia Commons)

They're Blue-Blooded Not in the bourgeois, 1 percenter sense of the word, though. These creatures really do have blue bood. That's because the oxygen-binding protein in their blood, hemocyanin, is blue. Image: Cuttlefish. (FireFly5/Wikimedia Commons)

Unafraid of the Dark Humboldt squid live in darkness, at depths of more than 3,200 feet. They only come up to the surface to feed at night. Image: Humboldt squid observed 1700 feet deep in Monterey Bay. (Zeidberg et al./PNAS)

They're Into Sex. "All male cephalopods have a specialized arm that they use to pass a package of sperm from their bodies to the females," Ellen Prager, author of Sex, Drugs and Sea Slime, told Wired in a 2011 interview. "But in the male blanket octopus, he actually self-amputates his arm and gives that to her as well." What a giver. Other squid, like Octopoteuthis deletron, also known as the octopus squid, will mate with just about any squid, regardless of gender. At more than 1,600 feet deep, other squid can be few and far between, so carpe diem is the way to go. Image: Two blue-ringed octopi mating. (Roy Caldwell)

They Leave Tips. Octopus squids, or Octopoteuthis deletron, can shed the ends of their arms during an attack, ensuring a safe getaway from predators. What's more, these freed tips sometimes keep on moving. Eech. Image: Octopoteuthis deletron. (Monterey Bay Aquarium Research Institute)

They're Flashy. Cephalopods can change colors, turning their chromatophores on and off randomly. Image: Oval squid. (Nhobgood/Wikimedia Commons)

Un-picky Eaters. Cephalopods will munch on just about anything. They're largely carnivorous, but pieces of plastic and even chunks of other cephalopods have been found in their tummies. Vampire squid feast on dead plankton and crustaceans and feces. They're the only cephalopods that don't eat live meals. Image: Vampire squid. (Kim Reisenbichler / Monterey Bay Aquarium Research Institute)