Never piss off a moray eel, warns George Burgess, a marine biologist at the Florida Museum of Natural History.
"Just like how you don’t tug on Superman’s cape, you don’t get too close to a moray eel," says Burgess.
A snorkeler in Hawaii found that out first hand during a recent swim in Oahu's popular Hanauma Bay, which was caught on video (see above).
At first, a large moray can be seen wrestling with a smaller octopus. One or more of the invertebrate's tentacles break off in the eel's mouth, allowing the octopus to wriggle free. With a quick blast of its water propulsion system, the octopus shoots out of sight.
"It left a cloud of black ink as its calling card," says Burgess.
Octopuses, like squid, have a gland that produces dark ink. When they are threatened, they can release it into the water, confusing predators and concealing their escape.
"The octopus was in a life-and-death struggle, and it sacrifieed an arm or two for its life," Burgess adds.
Unlike some insects and lizards, an octopus can't release an appendage on command, but if one does happen to break off in a struggle the animals can often regrow the arm. In fact, it is that wily nature—as well as the remarkable flexibility and slipperyness of the animal—that might have led the eel to try to subdue its prey by coiling its body around the octopus.
Eels don't kill prey by strangling it to death, the way some snakes do, but wrapping their body around it can help them hold on. Octopus is a favorite food of morays, along with other fish and invertebrates. (Learn about the two battling moose found frozen in ice.)
It's possible the eel could have lunged at the snorkeler in order to scare the person away from the octopus arm it had just caught, Burgess notes, along the lines of a dog baring its teeth if someone tries to take its bone. Although morays have sizable, sharp teeth and look fierce, they are usually not aggressive toward people. Still, they can inflict serious bites, particularly if backed into a corner.
But it's also possible the moray was really lunging at its own reflection in the camera lens, thinking it was another eel threatening to steel its meal, says Burgess.
"Clearly the eel was not any too happy," says Burgess.
But both the eel and the octopus—as well as the snorkeler—will live for another day.