This is the blue dragon sea slug, also known as Glaucus atlanticus.

Blue dragons are part of the nudibranch family, a group of soft-body mollusks more commonly known as sea slugs. Though they look like the left-behind offspring of some alien creatures, these bizarre creatures are 100% Earth-bred. They’re actually not all that different from your average garden snail, just a lot more colorful… and often extremely poisonous.

Although they are all quite beautiful, with a wide range of colors and specialized appendages, the blue dragon is the most visually stunning and fascinating by far. When fully extended, it looks like an alien dragon flying through the water on their colorful tendrils, known as cerata.

The blue dragon, a hermaphrodite that can grow to about one and half inches in length, is actually carnivorous, and feeds on other pelagic creatures using its powerful sting to paralyze its prey.

Blue dragons are known to go after much larger creatures, including the notoriously lethal Portuguese Man o’ War. Not only is the blue dragon immune to its sting, it’s able to process the Man o’ War’s nematocysts, the cells that allow for that creature’s deadly sting, and store them in its own extremities.

So if you see one of these little guys floating in the water, DO NOT pick them up. Simply admire them from afar and wonder how nature came up with such an amazingly deadly combination.