I wanted to make some simple torus shaped egg cups, and ended up with this design.
It reminds me of a coral skeleton. Hence the name.
The White strong and flexible material works great for this. The porous surface means the eggs are really stable when placed in the torus.
The material is rated to 80 degrees C, so if you take an egg directly from boiling water and place it in the cup, it could deform. Most of us don't do that however, and if you are able to hold the egg at all, it is safe to use the cup.
I tried printing a version in gold steel too. Here , the temperature is no issue of course, but the lack of friction might be. The polished steel is quite smooth, so the egg is less stable than in the plastic version.