Thanks IPT. I was able to visualize the metallic thing you describe while reading your post. Imagine them spinning like little rotary shaver heads! For me the one longer polyp tentacle on the bottom adds to a feeling of "pokeyness".
Using Live View while shooting worked well for me with this. I was able to select the area on which to focus then zoom on that while dialing the focus ring.
I am also amazed at the pattern / coloring of the coenosarc. From 3 feet away, it looks like a continuous shade, but as one can see on closer inspection, it's quite mottled. For me there is usually a happy sense of surprise when viewing macro shots as interesting detail becomes evident that I don't see from a distance.