On the remote rocky shores of the western United States, low tide brings visitors to wave-splashed tide pools to marvel at ocean wonders usually hidden from view.
But recently, largely missing from the bounty are the biggest draw: a rainbow-hued array of starfish.
"I don't know what you would call it other than catastrophic," says Drew Harvell, a biologist at Cornell University, describing what is widely regarded as one of the worst marine disease events ever recorded.
"It's staggering, really, the millions of stars that have died. It is not apocalyptic or extreme to say that."
In recent years, millions of the starfish, also called sea stars, have had their legs curl up and pull away from their bodies, breaking the animals to pieces before they turn to mush, often in a matter of days.
Scientists have been left racing to figure out why.
Once densely packed onto the rocks and on the ocean floor, the key predators are simply missing from some locations, their numbers cut by 95 percent or more.
The phenomenon, called Sea Star Wasting Syndrome, was first noticed by rangers in Olympic National Park in Washington state in 2013.