Possible explanation of this fossil: The red outlines what looks like a root (? Holdfast, anchor ?, does anyone know how sponges anchor to the bottom?). The orange outlines a stem, and the yellow outlines the "flower". Perhaps there are two separate organisms here, or just the yellow is a sponge and the other something else.
The rock is limestone, it used to be limey mud. With all the other broken bits of echinoderms and shells, it was probably deposited at or near normal wave base and above storm wave base. If it is all one organism, it looks like a storm ripped it off the bottom and it was buried in the mud protecting it until it lithified.