I'm a Little Teapot
On a dive in the Lembeh Straits, I came across this small (3-4cm across the body) blue-ringed octopus. After observing it for a little while it started to pose for me. Although the blue rings aren't at their most vivid, this individual had started to show its markings when I captured this image.
Olympus EM5, Olympus 60mm Macro, 1/160s @ f16, ISO 200