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 mineral 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.
Self-sexing vanadium-secreting intestine-rock thing is actually called Pyura chilensis (terser, though less descriptive), and it’s found off the coast of Chile and Peru. Locals eat it raw or in stews, and non-locals describe the taste as “bitter” and “soapy” with a “weird iodine flavor.” Sort of what you’d expect from a meat-rock, I guess? Maybe that’s the vanadium, a mineral also found in crude oil and tar sands — creatures like P. chilensis can have up to 10 million times more vanadium in their bodies than is found in the surrounding water, for no obvious reason.
And this evolved. It evolved FOR REASONS. Personally, I think it evolved just to piss the rest of the world off with its complete disregard for your narrow human notions of existence. Pyura chilensis is tired of your crap, man. Come at him. Sure he looks like savory meat loaf. Sure his defense mechanism is looking like savory meat loaf. But even the locals say he tastes like soap. Just to piss you off.
Nature is awesome.