Summary

It's a dice tray that looks like part of a stone castle. It's got a little turret you can stand your mini in, and a smaller tray area to set your dice in.
Great to paint with a grey or brown satin paint or primer, then apply some washes to give it a weathered effect.

I designed the tray in MS 3D builder, then kind of "skinned" it with the walls and turret parts that I remixed from the linked customizer parts.