The Cloud or dark cloud floats randomly above Puddleby Island and allows access to snells that wouldn't otherwise be accessible.
In order to gain access to the Cloud, one must enter the South Forest mirror while the cloud is overhead.
In order to move the cloud, it must be powered by a mystic. The cloud can only move in two directions, however; towards the green portal and towards the purple portal. Choosing a direction is accomplished by activating the corresponding colored circle with in the Cloud control room; a cave located to the southwest of the snell with the mirrors on it. Since the green and purple portals are movable as well, the cloud can be moved to any outdoors snell that they can be placed in. In order to move the cloud to an outdoors snell that the portals cannot be moved to, one must move the cloud and a portal adjacent to the snell one wishes to access and then let the cloud lose power. The cloud will then drift and hopefully move over the snell one wishes to access.
The location of the cloud can be determined by looking off of the cloud, either via a hole or the side of the cloud. Also, an exile on the ground can be used to locate the cloud.