A friend uncovered this oddball today in the Late Ordovician (Sandbian) of eastern Missouri, in the uppermost part of the Plattin Group (a Platteville equivalent) or possibly the lowermost part of the Decorah Group. He's been finding a lot of weird fossils in that zone, including articulated cyclocystoids, but this one I'm at a loss on. Too wobbly for an orthoconic cephalopod, too much space between calcite elements for a crinoid column. Given the size, is machaeridian a possibility? What other ideas should we be considering?