Cloud Drifting

Cloud Drifting (雲流し) is a prison cloud in which a ship and its crew are sett adrift on a cloud after they commit a Class-5 crime. The crew stays on this cloud until they all die or the cloud dissolves. In the latter case everyone on the cloud and the ship will fall down from the sky.

Known Cloud Drifting Sentences
In 1322 AOS, the ship called St. Bliss that came from Bliss Kingdom was left on a cloud. The crew had died but left many things from Skypiea behind. The ship eventually fell down to the sea due to the cloud finally dissolving.

The Straw Hat Pirates were originally going to be sentenced to such a punishment as they refused to pay the penalty fee for illegally entering Skypiea, thus obstructing the White Berets, a Class-5 crime. However, they evaded this punishment by assaulting the White Berets' leader, McKinley, which led them to face an even worse punishment.

After Enel's defeat, the Shandian warriors decided to have the remaining priests sentenced to a deserted cloud, as they are no more than criminals without their "God". Gedatsu, who fell off the island due to his battle with Chopper, was the only priest lucky enough not to suffer this punishment.