The Mangy Rat is a tiny, but mean critter. It has a high defense, which accounts for many missed attacks against it.
The Mangy Rat first appeared during the limited time event, Animal Invasion, alongside a mix of Boars, Raptors and a couple of Sandworms in the "Wild Bunch" group. They also appear in the special encounter with the Rat King.
The Mangy Rat, along with the rest of the "Wild Bunch", now make infrequent attacks on a player's nation after the Raiders vs. Bottle Rockets special event.