Subject: There are two truly amazing facts known about bobtail squids from the genus Euprymna to which this colourful cutie belongs. One: they have two types of cells all over their upper body. One type excretes a kind of glue that makes sand grains stick to their back as a means of camouflage. The second type excretes a kind of acid that dissolves the glue so the squid can shed the coat of sand in one go which then dwindles down to distract a potential predator while the little squid makes his/her escape.
And two: When they are young they catch a certain type of glowing bacteria to develop their special light organ. They keep them there and feed them and in turn use the bacterial glow to match the light coming from the surface while swimming in the open. This way they can avoid being seen by predators lurking on the seafloor.
Technique: I did not get much time with this beauty. I got one or two shots before it buried itself in the sand to get away from me. I like the pose here but in the original image there was not enough negative space in front of the animal. I therefor stretched that area just a little bit to improve the composition.