When you think about mechanisms that animals use to avoid becoming dinner, clever adaptations like poisons or pointy spikes come to mind. But the Ostracod, a type of zooplankton, uses something a little more magical.
To avoid being eaten by a Cardinal fish, they excrete a sudden blast of luminescent chemicals that act almost like a personal safety alarm. The Cardinal fish has predators of its own its trying to avoid, so when an Ostracod its trying to eat suddenly bursts into light, it immediately spits it out and backs away so as to remain hidden in the dark murky depths. It's like the Ostracod is screaming for help, but relying on the knowledge that whatever comes to see what's going on, will be more interested in eating its attacker. [BBC via Notcot]