Squid belongs to Arthropoda, Crustacea, mollusca, Shrimp Subclass, Stomatopoda (there is an order below this subclass). All are marine. Shrimp predation originated from Jurassic in Mesozoic, and most species live in tropical and subtropical waters, with a few found in temperate waters. All along the coast of China.

Squid's big jaw is very hard, and its second jaw foot is particularly strong. Its distal segment (knuckle) is flat and has six sharp teeth, which can be matched with the edge groove of the metacarpal segment. It is a sharp weapon for preying and defending the enemy, and is called limb-sweeping.

Mantis shrimp, one of the shrimps, lives in the tropical waters of the Pacific Ocean. Its length can be up to18cm, and its appearance is made up of bright red, blue and green. It is a ferocious carnivorous arthropod. Usually, it lives in the crevices of rocks and reefs. If any prey passes by, it will attack its prey by sneak attack, just like a predator waiting for him, both male and female. After tens of millions of years of evolution, mantis shrimp's front claw hook has evolved into a pair of powerful "spring iron fists". When a prey comes near, it knocks it hard on the prey with the elastic front claws, and more than once, mantis shrimp will give more pursuit as the case may be, just as a boxer quickly attacks his opponent with a jab, but mantis shrimp's jab is more powerful and faster.

Mantis shrimp's second pair of jaws is very developed, which is a sharp weapon for it to prey and defend against the enemy. The front-end section of its catching limb is a single thorn, the end is as sharp as an awl, and the root is raised and thickened. When it is folded, the thickened part can break the hard shell of crustaceans, shellfish, snails and other animals like a hammer; And when it is stretched out, it can easily pierce the soft tissue of animals. When attacking prey, it can eject the front end of the catching limb in one fiftieth of a second. A pistol bullet with a top speed of more than 50 miles per hour (about 80 kilometers) and an acceleration of more than 0.22 inch (5.588 mm) can produce an impact force of up to 60 kilograms. The high temperature caused by friction can even make the surrounding water emit electric sparks. Once a scientist was caught in the sea wearing gloves and hurt his fingers, bleeding profusely. Brought back to the laboratory and put in a measuring cylinder, the measuring cylinder was also smashed by it, which was fierce.

Mantis shrimp's "weapon" is light and impact-resistant, and it will not be damaged until it is struck 50,000 times. Mantis shrimp will make up for the loss of his "weapon" by shedding his skin periodically.