The Hawaiian bobtail squid might be small, but this walnut-sized critter is one of the sea’s mightiest masters of disguise. During its evening jaunts, the squid protects itself by casting an eerie glow to match the moonlight, obscuring its silhouette to predators lurking in the water column below.
This cloak of invisibility is an illusion by collusion, all thanks to a luminous cache of Vibrio fischeri bacteria held within a specialized chamber within the squid’s body called the light organ. In exchange for canceling out the squid’s shadow, the microbes receive housing and a stipend of sugars.
But it’s now clear that these microbes do far more than conjure a cloak of invisibility.