This thing in the center of the photo right above the polyps is what I'm wondering about. It came as a hitchhiker on the live rock. I've always just assumed it was a duster but it grabbed ahold of a couple mysis shrimp recently and it forced me to take a closer look. It's got these yellow bumps on the end of its arms which is now making me think its an anemone of some kind. Usually can't get a photo of it at all cuz it's very dark but it's got a belly full of shrimp making it easier.