Asteroids in this group feed by eversion. The animal humps over a coral colony, extrudes the cardiac stomach through the mouth on its underside, and presses the everted tissue against the coral. Digestive enzymes released there break down the coral polyps where they sit, and the liquefied tissue is absorbed before the stomach is drawn back in.
The visible result is a feeding scar: a patch of white skeleton where the coral tissue has been stripped away, often the size of the starfish's own disc or larger. A single adult can clear on the order of several square metres of coral in a year, though the figure varies enormously with coral type, water temperature and the animal's size.
The common misreading is that outbreaks are simply an invasion of an alien pest. The species is native across the Indo-Pacific and is a normal reef inhabitant at low density. What is disputed is why numbers periodically explode, with nutrient runoff boosting larval survival and the loss of predators both proposed and neither fully settled.