There are many unique and unusual creatures that live under the sea. Many of these creatures belong to the Cephalopod class—which includes squid, ocotopus, cuttlefish and nautilus. Cephalopods are characterized by their bilateral body symmetry, prominent heads and sets of tentacles.

There are approximately 300 different species of octopus and they're mainly recognized for having eight tentacles. They're among the most intelligent and behaviorally diverse invertebrates. They're able to complete mazes and solve problems, which shows their capacity for both short and long-term memory. Some in laboratory studies have even been able to differentiate between shapes and patterns. They're also known for being impressive escape artists, able to sneak their way out of aquariums, enclosures and even jars. Octopus have been featured prominently throughout popular culture, appearing in "Finding Dory," "Toy Story 3" and "Shark Tale."

Another fascinating Cephalopod is the squid. There are approximately 300 species of squid within the animal kingdom. Squid are similar to octopus, in that they are mainly soft bodied and can use camouflage for protection, however, there are some key differences. For example, they have eight arms and two tentacles. Second, they possess a small internal skeleton. Squid have also appeared in many films and television shows, most notably seen through Squidward Tentacles of "SpongeBob SquarePants."

For all those enchanted by octopus and squid, we've brought together 50 tattoos from talented artists around the world. Take a peek at their extremely impressive work in the gallery below, then let us know your favorite piece from this list in the comments section on social media.