Plague Rats
Plague Rats is a perk that causes rats to no longer harm you, and summons different colored plague rats when enemies die. Plague rats are much stronger than regular rats, but disappear after a while. They are good for combating and distracting groups of ground based opponents.
The damage and HP of plague rats scales with how deep you are in the world.
Rats will attempt to harm you if you hit them with friendly fire, are under the effects of 
Berserk, or possibly with the More Hatred perk.
Stacking
Additional stacks cause additional plague rats to spawn when enemies are killed.
Transformation
When you have Plague Rats, Revenge Rats, and Spontaneous Generation, you will be granted the Ratty Transformation which causes you to grow a rat tail and gain a 15% boost to your horizontal movement speed.
History
- Nov 5 2019: Added to the game.