VIDEO: Octopus Fights Shark

This video shows a brutal fight for survival between a shark and an octopus.

Think you know the outcome? Think again!

According to Live Science, octopuses are ocean creatures that are most famous for having eight arms and bulbous heads. Some other fun facts: They have three hearts and blue blood; they squirt ink to deter predators; and being boneless, they can squeeze into (or out of) tight spaces. They are quite intelligent and have been observed using tools.

And sadly, for them, sex is a death sentence.

Some people call their appendages tentacles, but that is incorrect; they are arms. Most octopus species have suction cups on the bottom of each arm. The arms seem to have a mind of their own.

In fact, two-thirds of an octopus’ neurons are in its arms rather than its head, according to the article. That means that an octopus can focus on exploring a cave for food with one arm while another arm tries to crack open a shellfish.

Some octopuses even have warts. Two deep-sea octopuses in the Graneledone genus — G. pacifica and G. verrucosa — have skin bumps dotting their pink-hued mantles. These warty protrusions, it turns out, can be used to distinguish the two species, which have been incredibly difficult to tell apart.

Scientists reporting June 7, 2017 in the journal Marine Biology Research catalogued the distribution of warts on both species, pinpointing two variables that were consistent across the individuals within a given species: distance between the warts and the tip of the mantle and the extent to which the skin bumps spread down the creature’s arms.

Octopuses have an excellent sense of touch, according to the World Animal Foundation. Their suckers have receptors that enable an octopus to taste what it is touching.

Most octopuses — those in the suborder Incirrata (or Incirrina) — have no internal skeletons or protective shells. Their bodies are soft, enabling them to squeeze into small cracks and crevices, according to National Geographic.

In April 2016, an octopus at the National Aquarium of New Zealand squeezed out of its tank and made an eight-armed dash for a drainpipe that — luckily for him — led directly to the sea.

A bulbous sack-like body, or mantle, is perched on top of an octopus’ head. The only hard part of their bodies is a sharp, parrot-like beak that is on the underside, where the arms converge. Octopuses have powerful jaws and venomous saliva, according to National Geographic.

Octopuses weren’t always squishy creatures. The ancestors of octopuses and squid sported hard shells.

A study published online March 1, 2017 in the journal Proceedings of the Royal Society B: Biological Sciences revealed these marine animals lost their hard “mobile homes” in the Jurassic and Cretaceous periods. This shell loss likely helped the ancient relatives of today’s octopus, squid and cuttlefish become more agile to evade predators and nab prey, the researchers said.

An octopus has three hearts. One pumps blood through its organs; the two others pump blood through its gills, according to the World Animal Foundation. Octopus blood is blue because it has a copper-based protein called hemocyanin.