I was beachcombing on Treasure Island yesterday and spied this weird item coiled up like a snake or a centipede. Although it's most likely a sea plant of some sort, I initially was sure it must be something more; it felt very meaty and heavy like a dead snake. However, a dead critter of that sort usually loses its coiliness after death, and this thing stayed defiantly sproingy despite my attempts to uncoil it as best I could using a stick.
On close inspection, it seems to be segmented like a slinky, into little spiny circles all connected to a "vertebrae". I spent a few minutes on the Googles and didn't find anything like this in the vegetable or animal kingdoms, but I didn't look too hard because I am a profoundly lazy man. Anyone recognize this thing?