Blue dragon (Glaucus atlanticus)

This small creature, so similar to a space alien, actually belongs to the class of gastropods.
They live in temperate and tropical waters around the world, and are most often found on the coasts of Australia and the United States.

They spend their entire lives simply drifting with the current belly up on the surface of the water in search of food. They feed on coelenterates - siphonophores, jellyfish, veella.

The dimensions of gastropods are simply tiny - only 2-3 centimeters in length. But sometimes there are individuals that reach eight centimeters.
The blue or blue abdomen hides them from the birds from above, camouflaging them under the water, and the white or silvery-gray back hides them from the fish from below.

Nature