When it comes to taking hardcore evolutionary paths, some animals don’t hold back. The common sea urchin, as it turns out, really drives this point home—boasting a spiky nervous system scattered throughout its body, including light-sensitive cells resembling structures in human eyes.

Imagine ordinary sea urchins —roundish, spiky creatures minding their own business on the sea floor. According to a recent Science Advances paper, this assemblage is the sea urchin’s entire body—or, rather, head. That is, sea urchins don’t have a multi-part body, just a head, which is comprised of a remarkably complex nervous system forming an “all-body brain,” as the researchers describe it in a statement .

Importantly, this nervous system isn’t a hodgepodge bunch of neurons but rather a sophisticated

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