The sea urchin (uni to the Japanese) is a fine reminder that aliens live among us. Like the sea cucumber and starfish, its anatomy follows a five-point symmetry. It walks on tiny tentacles attached to long, sharp spines. Its mouth and five claw-like teeth are on the bottom of its spherical shell; its anus pokes out from the top. And its gonads happen to taste delicious.
Although uni is often called sea urchin roe (that is, eggs, like caviar), the creamy orange lobes of briny-umami delight that is uni are actually the urchin’s version of ovaries or testicles. The urchin has five of them, nestled deep within its hollow shell near the anus, and they’re the only edible part of the whole animal. If that makes you uncomfortable, we have bad news for you about apples: those are a fruit tree’s ovaries as well.