Cool - that was my best guess...just haven't been able to find any info or images of any like this, so wasn't certain. Any idea what time period it would have lived in? What kind of oyster it is? I find a lot of Devonian and Ordovician fossils in my area (mostly different kinds of crinoids and corals), but my research material hasn't turn up anything looking like this guy. I am thinking it's not nearly that old, but I am at a loss since I haven't found anything in any time period that looks enough like it for me to go "AHA!".