That's not a cloud. That was a large globule of sea foam which was probably generated by the nearby dredging operation. Gulf Arab countries, especially Dubai, use enormous hoses to spray a slurry of sand and seawater in order to sculpt artificial islands like this one.
During roughly the first half of the video, you can see the fountain spraying in the distance. It's faint, but you can see it arching off to the left.
You can tell it's not a cloud because of the way it rotates as a solid body. Clouds are made of water vapor, a gas.
Also, a cloud on the ground would not be a unique, or even unusual, occurence. There have been plenty of clouds on the ground before. It's called fog.