A mysterious disease is killing millions of starfish, and now it's having a profound effect on the food chain.
Scientists say the sea urchin population has grown and they now cover the sea floor off the coast of Monterey.
Starfish used to prey on them and kept their numbers in check
Scientists say sea urchins will soon mow down giant kelp forests, which are home to other ocean creatures.
However, sea otters could also help. They are the only predator right now to keep the surplus of urchins in check.