Thousands of meters below the ocean’s surface is a tiny jelly with what looks like Iron Man’s arc reactor. But unlike Tony Stark, Atolla jellyfish use their glowing blue chests to attract bad guys, not fend them off.
In the blackness of the deep ocean, organisms don’t use light to see. Rather, the ability to illuminate a portion of the body through bioluminescence is used to distract, lure, and evade with blips, flashes, and pulses of typically pale blue light. The tiny Atolla jelly uses its manufactured light to raise an alarm.
Scientists dubbed this display a “burglar alarm” not for how it looks, but for its speculated purpose. There isn’t much a for a jelly to do if a nimble predator like a squid comes along. So instead of fleeing when attacked, the Atolla will start its mini arc reactor in the hopes that a bigger predator will see it blinking in the black.
If the display is successful, then either another hungry mouth will scare off or eat what is after the Atolla or populations of predators will evolve to be wary of the little jellies.
And Atollas are not the only miniature Tony Starks in the ocean. Another organism, a small crustacean called an ostracod, secretes chemicals when swallowed by a fish with the same hope that a larger predator will notice what just happened. It’s effective enough that ostracod eaters spit-up the crustaceans when they light up, and they make it look like fish are casting patronus charms: