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- Some animals do not just change beneath the moon; they change into the moon. During the day, bobtail squid—speckled, peanut-sized cephalopods related to cuttlefish—bury themselves in sand to rest and hide from predators. At night, they emerge to feed on shrimp and worms. Having abandoned the seafloor and exposed themselves to potential danger, the tiny mollusks cloak themselves in an entirely different kind of camouflage. Bobtail squid have evolved one of the most magical symbioses on the planet. Bioluminescent bacteria live within the folds of a chambered sac in the squid’s mantle, generating light that spills from the squid’s underside. A lens and color filter attached to this internal lantern—known as the light organ— modulate the microbial glow to mimic the light of the moon and stars filtering down through the water. In this way, bobtail squid erase their own shadow. Instead of seeing a conspicuous squid-shaped silhouette, any predator gazing up from below sees only more moonlit sea.