Ambient entities

Ambient entities are objects that appear and move around in the background. They are also un-interactable. They depend on the time of day, biome, and weather. Some are rare, and some are very common. They are completely uncontrollable by the player. Clouds can be considered background entities although they aren’t affected by biomes. Ambient entities speed up with time.

Rare clouds
Every time a cloud spawns, there is a chance it will instead be one of these rare clouds.