From Guild Wars 2 Wiki
No Clouds are NPCs found inside Super Adventure Box that block players from a location or route. They are mostly found in Tribulation Mode to prevent players from going a way other than the intended route, though one also appears in the Hub to prevent players from going inside the hole where the NPC parade starts and ends.
- Rata Sum
- Cannot be attacked or killed.
- Is completely immobile.
- They appear instantly if a player gets close, and will disappear after about 3-5 seconds. It will instantly reappear if the player tries to go the wrong way again.
- A few seconds after it appears in Tribulation Mode, the No Cloud will electrify itself. This will knock back anyone within a short range.
- May be used as a stepping stone. Be sure to do so only before or after it has used its electric attack.
- It has no official name, but Anet staffers working on SAB nicknamed it the "No Cloud", and players often refer to it as the "No No Cloud".