The wild looking “living rock with guts” is actually called Pyura chilensis and resides off the coast of Chile and Peru. Apparently locals like to eat it in stew.
Jess Zimmerman at Grist has more information:
The fact that this sea creature looks exactly like a rock with guts is not even the weirdest thing about it. It’s also completely immobile like a rock — it eats by sucking in water and filtering out microorganisms — and its clear blood mysteriously secretes a rare element called vanadium. Also, it’s born male, becomes hermaphroditic at puberty, and reproduces by tossing clouds of sperm and eggs into the surrounding water and hoping they knock together. Nature, you are CRAZY.
This odd reproduction process is called “selfing.” Read more here.