Hidden eggs are unable to hatch, but if it has enough views to hatch, has a low amount of time, and it was hidden before it was able to hatch, it will hatch when unhidden. The same applies to hatchlings while growing up- they are still able to gender while hidden but will only grow up when the correct number of views and low time is met and they are unhidden.
Neither the owner of the creature nor other users can view its lineage while it is hidden in fog. The owner also cannot use any Breed Specific Actions such as Influence on a fogged egg - it must be unhidden for the BSA to be used. Eggs and hatchlings currently being teleported cannot be hidden until the teleport is cancelled.
When the player hides an egg or hatchling, this message is displayed:
- "You cast a spell to hide the egg/hatchling in a thick cloud of fog."
When the player unhides the egg or hatchling, this message is displayed:
- "You magically dispel fog around the egg/hatchling."
Only the owner can see the dragon's info page while it is hidden. Other users will see:
- "You can't seem to find the dragon you're looking for."
When something is hidden, its usual sprite will be temporarily changed to a large mass of gray fog so nobody can see what the creature is or its information. Eggs and hatchlings with the fog sprite are often called "fogballs" by users.
- The Glitch Dragon shares the same sprite as a hidden creature.
- There was once a glitch where the egg of a Nocturne Dragon showed up as fog on an incubator.
- If the page that says "You cast a spell to hide the egg/hatchling in a thick cloud of fog" is refreshed, it will unhide the egg/hatchling. (This works vice versa, too.)
- Fogging was originally thought of as a concept BSA for Storm Dragons to combat Dragon Sickness.
- A hidden creature's time until death is occasionally extended, with its timer showing "0 days". Normally, an egg/hatchling's time is rounded up, so one with 0 days and no hours should have died.
- On August 13, 2015, the hide/unhide action messages were changed. When the player hid or unhid an egg or a hatchling before then, the following messages were displayed:
- "You hide the egg/hatchling in a thick cloud of fog."
- "You dispel the fog around the egg/hatchling."