A female Pacific blackdragon is ~60 cm (2 ft) long and uses a bioluminescent lure on her chin to attract prey. Her skin is 'ultra-black', among the darkest in nature, and her teeth are anti-reflective, so as not to reflect light from her lure and alert her prey. The male is only ~8 cm (3 in) long.

The coconut octopus carries seashells or coconut shells beneath its arms as it travels — using a few of its arms to hold the shells and the others to walk awkwardly along the sea floor. If this octopus encounters danger, it assembles the shells around itself, forming a kind of armour.