I spot one on a clear September morning, while swimming through the lukewarm waters around the Great Barrier Reef. A striking starfish, the color of cabernet and sporting more than a dozen arms, hugs the side of a gently curving ridge of coral. It looks lovely and dangerous, and not just because I know the long spines covering it are lacquered with venom.
This creature, located a two-hour boat ride from Townsville, off Australia’s northeast coast, is known as the crown-of-thorns starfish. While it’s the first one I have ever seen, it’s far from alone. Since 2010, a plague of them, numbering somewhere in the millions, has been methodically consuming the Great Barrier Reef, representing yet another in a series of existential threats to a coral reef system already wounded by intense hurricanes and weakened by bouts of exceptionally warm waters.
Nor is this the first outbreak. Since 1962, their populations have skyrocketed to “outbreak” status on the reef roughly every 17 years, starting north of Cairns and spreading south in waves, the free-floating larvae carried along by currents. After settling on a reef, they transform into tiny stars, impossible to spot. They don’t start eating coral until reaching at least six months, while still smaller than a dime.
But from there, they begin to grow and eat in earnest, soon resembling their biblical namesake. The starfish become an army that marches on stomachs extruded from their mouths, digesting the thin layer of living coral beneath them, favoring the quicker-growing corals, the hardest hit by bleaching brought on by rising sea temperatures.
All of which is a way of saying: Clearly, this creature before me needs to die. But the two scuba divers whose task it is to kill crown-of-thorns along this reef are nowhere in sight. Before long, the prickly, peckish villain has disappeared. This is where the killer robots come in.