Special Plagues are expansion packs of Plague Inc. They can be unlocked immediately for $1.99, or unlocked by by beating all previous plagues in Brutal difficulty. For some, these plagues can be more difficult than the standard. They are unique, having different transmissions, symptoms, and abilities. They also have their own theme and interface.
In Plague Inc. for mobile, special plagues are located under a tab in the lower right-hand corner.
Cheat plagues are a type of special plague which makes it easier to win a game.