Rat

Rats are a humanoid faction appearing in Borderlands 2. Whereas Bandits inhabit the wastes of Pandora the Rats occupy the urban or urban ruins of the planet. Ostensibly under the direction of the Sheriff, Rats patrol and raid to keep her entertained.

The Rats wear gas masks, as they once lived in toxic mines and tunnels. Over time they mutated by growing long claws and shrinking in size and stature and also obtaining a taste for human flesh. When they collect people to be sacrificed and eaten, midgets and other bandits are often on the menu. They also have a large, over extended right arm. The masks have become a sign of their status, and they wear them now for ceremonial purposes.

Very much like actual rats, this faction will grab and make off with loot. This may lead to interesting decision points as a player weighs the benefits of defeating a threat or pursuing a rat which has acquired a valuable loot item. Defeating a hoarding rat will result in a burst of scattered loot. Additionally, due to their cannabalistic nature, they can regain health by devouring corpses.

Types
True Vault Hunter Mode
 * Tunnel Rat - The basic and most common type of Rat encountered on Pandora. They are not very durable and as such will try to stay as far back from their enemies as possible, shooting at them with assault rifles and ducking and weaving away from enemy fire. In the case that an enemy gets too close, they will either leap at them or hit them with a claw swipe to knock them away. If there is any loot on the field, they will run over to it and pick it up. If left alone long enough after picking up loot, they will bury it and the loot will become unrecoverable.
 * Field Rat - A stronger, tougher, faster and more evasive version of the Tunnel Rat and like Tunnel Rats, they try to stay back from their enemies and pepper them with assault rifle fire. However, unlike Tunnel Rats, occasionally they will go in for a quick melee strike which is usually done via a powerful long-distance leap that is capable of knocking enemies back. They will also stop to pick up any loot they find on the battlefield.
 * Rat Thief - Unlike other Rats, Rat Thieves have almost no interest in fighting, instead, they are interested in pilfering a sizeable chunk of money from unsuspecting travelers. Rat Thieves move quickly, quietly and often from behind their targets. If a Rat Thief is successful in his attempt to steal money, he will quickly scamper off to bury his newfound treasure, like other Rats. If he successfully buries the money he has stolen, it will become unrecoverable. The money can be recovered if the Thief is killed before he buries the money.
 * Midget Rat - Diminitive and substantially weaker versions of Tunnel Rats. However, unlike Tunnel Rats, they tend to close in on their targets a little bit and their heads are fairly large, making for easier critical hits.
 * Lab Rat - Lab Rats are almost polar opposites to the other Rats: they are slow moving and inevasive, have an incredible amount of health, do not pick up loot or items on the ground, and attack mainly from close range. The only time a Lab Rat will attack from a range is when he cannot reach the player and at that point will begin to toss a Buzzaxe in a manner similar to a regular Psycho. If they get close to the player, they will unleash a devastating eye-laser attack that can quickly destroy shields and sap the player of a substantial chunk of their health. Also, as they advance towards the player, they will cover their face with their massively mutated right arm, making it harder to score a critical hit.
 * Miner Rat - A slightly stronger version of the Tunnerl Rat found exclusively in the Tundra Express. They fight and move in a manner similar to Threshers, in that they move underground, reappear topside to strike, and then dive back underground to move to a different location. Like Threshers, they cannot be hurt while underground.
 * Bloody, Crabby, Creppy, Dirty, Greedy, Sleazy, Tipsy - Named Midget Rats that appear in the fight with Scooter's crush, Laney White, during the Mission "The Cold Shoulder" in The Fridge.
 * Plague Rat

Badasses

 * Loot Midget Rat
 * MDK Assassin Rouf
 * Dan, Lee, Mick & Ralph
 * Laney White
 * Mortar
 * Flinter