Vortex Cube

The Vortex Cube is a very old and powerful item, a black cube that can be used as a container. If the eight Moonstones of Britannia are stored into it, it has the power to draw and return objects from the Ethereal Void. But even without the Moonstones, the Vortex Cube is still powerful enough to allow teleporting through Britannia.

The Vortex Cube was used by Naxatilor to draw the Codex of Ultimate Wisdom out of the Void. After that, it was stored in their museum. However, it was stolen by human thieves prior to Ultima VI and taken to Stonegate via the Bay of Lost Hope. In Ultima VI, the Avatar found the Vortex Cube in the cellars under Stonegate, and a cyclops claimed possession of it. Used together with the Moonstones and the Lenses, the Cube returned the Codex to the Void. After that, the Vortex Cube had lost its purpose, and it was moved to the Museum in Britain, where it could be found in Ultima VII and IX.

Trivia

 * The Vortex Cube was totally screwed up in Ultima IX. It wasn't any longer a cube, and flickered all the time. However, the Vortex Cube in the other Ultimas are black and...a cube.