There are times when life imitates art. Then there are times when life imitates science fiction.

One of the most famous monsters in film history is the extraterrestrial beast of the “Alien” series. It slowly opened its glistening fangs to reveal a second set of jaws that shot forward to kill its victims.

Scientists have now discovered a fish that does the same thing.

Rita Mehta did not have aliens in mind when she began to study the moray eel. Dr. Mehta, a postdoctoral researcher at the University of California, Davis, where she studies the evolution of feeding, was intrigued by the dining habits of morays.

They are impressively successful predators, able to devour large fish whole, and they grow to more than 10 feet long. Unlike other big-fish predators, morays have no fins. They hide their snakelike bodies in the crevices of coral reefs, waiting to strike. “No one knew much about their feeding behavior,” Dr. Mehta said.

Morays belong to a group called ray-finned fishes that includes a vast majority of fish species, like tuna, goldfish, salmon and trout. Most ray-finned fish use suction to eat. To catch prey, they suddenly expand their mouth cavity. The negative water pressure sucks in the prey.