My fiancé Loves shells, so I designed this ring holder and dish for her to use to keep her rings when she is not wearing them. I tried to design it without the need for much support material, but any that your slicer adds under the shell could probably be left in place, and just two of the horns or spikes should need a slight amount of support.

V2: Made a small patch to fix up the hole referenced by the first maker. I don't know how I missed that when I was building the model.