This is a bubbling cauldron, sized for 28mm figures. Josen made a good one, but I wanted it to be bubbling and the right size for D&D. I also used a base from https://www.myminifactory.com/object/3d-print-bases-platforms-for-miniatures-86097

You can print it out full or empty, and you can make the contents a separate piece, in case you want a different color, or the ability to change it out.