Rats

The rats are tertiary antagonists in the game. Unlike Granny's other pets, they appear to be ghostly and incorporeal in nature. As a result, they only appear when nightmare mode is enabled.

They are normally docile and playfully curious, but are not completely harmless.

Appearance
The rats look like standard white rats, but have some strange paranormal properties. They are transparent and are followed by a trail of white mist, suggesting that they are not actually alive, but rather spirits of their formerly living selves.

Behavior
The rats start the first day somewhere around the basement, and will immediately begin wandering the house upon the player waking.

They follow no set patterns, and can move around the house much more freely than Granny can, often entering areas that she normally does not have access to. They still are not able to enter crawlspaces, however, interestingly enough. They are able to run through doors and certain obstacles as if they aren't even there.

When they have reached their current destination, they will stand idly for 10-30 seconds, before picking a new spot to run to, the cycle repeating indefinitely.

Problems start to arise when they are near the player, however. While they are not directly hostil, they will be startled if stepped on and will bite in self defense before running away. This bite will injure the player, shaking their screen and splattering it with blood. On the PC version, it will also result in a thick vignette darkening the edges of the screen and a lens distortion effect will be applied, messing with the player's perspective and overall making it more difficult to see. They will also squeal, which will get Granny's attention and call her to their current location.

The effects obscuring the player's vision will eventually fade, leaving no permanent injuries and not advancing the day count.

Something interesting to note is that the rats seem to be capable of teleportation, but only under very specific circumstances, which are not currently known at the time. It seems to happen most often when the player is chasing them and they manage to get out of view. When this happens, they will simply disappear, leaving only white smoke behind, before reappearing elsewhere in the house.

Sounds

 * The rats being stepped on by the player
 * The rats being stepped on by Granny (or shot with tranquilizer dart)

Trivia

 * The rats seem to be afraid of Granny as well, squeaking and running away when she steps on them. Regardless, this does not seem to hinder or affect her in any way.
 * The rats are completely immune to all weapons. Strangely, they will react to being shot by a tranquilizer dart, but will completely ignore a shotgun blast regardless of distance.
 * The rats' model can be found in a package from the Unity Asset Store, titled Wild Life: Random Beasts.