Thanks Jim, I removed the offender from my tank. Hopefully, it's the only one. It was on a new clam I got and I noticed it the first day, took a picture the next day, and pulled it out after finding out it was bad. It's sitting on top of my tank in a small container, when I get the chance, Ron Shimek asked me to send it to him, so I'll do that. I've been keeping an eye out for others in the mean time, and if I see any more, they'll be removed immediately. This one seemed to be attached to the shell just under the mantle, does that seem like their usual routine?