Stone have an octagonal shape with different hues of dark green. They have a trillium like symbol in the middle with other shapes within the stone. It looks similar to the bombs in the same game.
For the majority of levels that the stone appears in, a cannon will also appear. This is because cannons are the only objects that can grant stones mobility. They are usually intrinsic to the solution of a level. Stones first appear in level 7A of Under Dwell. Stones can be tied down to other objects with the use of chains. This adds extra weight onto the objects, which makes it sink faster and launch at a lower distance when a cannon is used. Stones can also push other objects towards a certain direction.