You'd be forgiven for thinking this was something out of the film Alien.
But it's actually a giant mantis shrimp.
A couple reeled in the enormous creature while fishing at Florida's Fort Pierce.
According to the Metro, onlooker Steve Bargeron took it off the couple's hands but ultimately decided against taking it home.
He did make sure to take lots of pics before he put it back in the water, though.
While the animal looks, as Bargeron described it, like an "alien creature", it's actually not that uncommon.
According to Roy Caldwell, a professor of integrative biology at the University of California, Berkeley, the creature is a mantis shrimp, or stomatopod, a marine crustacean commonly found in the waters off Florida, reports Live Science.
Mantis shrimps often reach 30 centimetres (12in) in length, though in exceptional cases can reach 38cm (15in). The longest mantis shrimp to date measured in at 45 centimetres (18in) long.
There are more than 400 species of Mantis shrimp. They come in a variety of colours, from shades of brown to bright neon colours and are among the most important predators in many shallow, tropical and sub-tropical marine habitats. Despite being common, they are poorly understood as many species spend most of their life tucked away in burrows and holes.
The are sometimes referred to as "thumb splitters" – because of their ability to inflict painful gashes if handled incautiously.
Mantis shrimp sport powerful claws that they use to attack and kill prey by spearing, stunning, or dismemberment. In captivity, some larger species are capable of breaking through aquarium glass with a single strike.