Thousands of Rare Sea Creatures Wash Up on Texas Beaches In a Massive ‘Die Off’

The Texas coastline is seeing a rare and unusual sight: thousands of mysterious sea creatures washing ashore after what experts are calling a “mass die off.”

The creatures, commonly known as sea potatoes, are actually heart urchins—a type of invertebrate related to starfish and sand dollars. They usually live buried beneath the sand, which makes encountering one—or its skeleton—especially uncommon.

“The biggest news this week has to be the mass die off of these sea potatoes, aka heart urchins,” Jace Tunnell, community engagement director for the Harte Research Institute in Corpus Christi, said in a Facebook post on Friday, January 9. “Literally thousands and thousands washing up along at least 60 miles of Texas beach that I surveyed this week.”

Heart urchins typically spend their lives underground, burrowing slowly through the sand and extracting nutrients. They move just about two centimeters per day and live on average three to five years, though some can live as long as a decade. Live heart urchins are covered in fine spines that look like rough, short hairs, making them look very different from the pale skeletons now littering the Texas Gulf Coast.