This is on a piece of life branch
It opens only at night (tentacles out) it has not moved in 4 weeks -- so must be sessile
the stalks are clear with white "balls" at the ends (unbranched)
size of a nickle closed and closed to .5 dollar size open.
When closed looks hard (have not touched it) --just really curios what it is -- note it has "sand dollar marking when closed)