I received a very cool fossil a few months ago from a seller on E-bay who specializes in the trilobites from the St. Petersburg region of Russia. I'd asked them if they had any other fossils besides trilobites and they came back with a small lot of mixed invertebrates. Among that lot was this echinoderm that is called Bolboporites sp. It is classified as an eocrinoid but looks more like a Hershey's Kiss. It was attached to the sea floor at the narrow tip (or possibly partially buried) and had just one arm that was attached to the flattened top (see the last pic). It is still something of a mysterious fossil as not much else is preserved of them.
This fossil came from the Volbokalo quarry near St. Petersburg Russia which mines rocks that are part of the Kunda Horizon, Asaphus expansus Zone of the Lower Ordovician.
I found a paper on Bolboporites here. An it was featured on Wooster Geologists blog as a Fossil on the Week.