The Blue Dragon Sea Slug (Glaucus atlanticus) has several names. It is also known as a Sea Dragon, Sea Lizard, Blue Ocean Slug, Blue Glaucus and Sea Swallow. This little creature measure about two inches in length and is one of the most beautiful of the oceans' inhabitants with its striking blue coloring; however, its beautiful appearance is deceiving as it has quite the sting from the tendrils that make its tail. The sting comes from nematocysts a poison that is usually found in cnidarians, but the Blue Dragon Sea Slug is not a cnidarian.
Their favorite food is the potent Portuguese Man o' War. This tiny little slug can cut large pieces from large prey using their radula tough toothy tongues that are found in all mollusks. They also feed on the Blue Button and By the Wind Sailor, who is also a poisonous hydrozoan. They have also been known to cannibalize other Blue Dragon Sea Slugs when their natural prey is unavailable. The Blue Dragon Sea Slug is immune to the stinging cells they are so fond of; this is because their stomachs do not digest the nematocysts. These amazing creatures suck the poison into the fingers of their tails and there are eighty-four of these equipped with small sacs called canidosocs in each finger. The tail with its many fingers is often called jazz hands. The stings are accumulated until they are needed to protect themselves against predators. Their stings are more toxic than from the Portuguese Man o' War because the Blue Dragon Sea Slug is very selective and takes in only the strongest and most developed for their needs.
They can be found around the world in temperate and tropical waters floating freely upside down with its blue foot resting above its body. As it is floating around the silvery back faces down helping to camouflage this small slug in its natural habitat. They are equipped with gas sac inside its stomach that is used for the sole purpose of floating in the water, where it floats is dependent upon the direction of the wind. The Blue Dragon Sea Slut is hermaphrodite, and both lay a long chain of eggs floating in the water on driftwood or even on the skeleton of prey they devoured. When the larvae hatch they are equipped with shell similar to a snail that they soon grow out of, stretching out like the adults finding the appropriate prey to fill their fingers with the stings needed to protect themselves from predators.
Because their stings are deadlier than those of the Portuguese Man O' War, it would be wise to watch for them in the waters while visiting the beach for a day of swimming or surfing.