Enemies

The are three general types of enemies found in Borderlands: creatures, humans, and Guardians (aliens), all of whom can come in a Badass (1st Playthrough), BadMutha (2nd Playthrough) version, or SuperBad (After 2nd Playthrough).

Creatures

 * Adult Skag
 * Alpha Skag
 * Crab worm larvae
 * Gyro Spiderant
 * Rakk
 * Rakk Hive
 * Scythid
 * Skag Pup
 * Skag Whelp
 * Soldier Spiderant
 * Spitter Skag
 * Trash feeder
 * Worker Spiderant

DLC

 * Skelerakk
 * Corpse Eater

Guardians

 * Arch Guardian
 * Badass Guardian
 * Guardian Wraith
 * Guardian Spectre
 * Principal Guardian
 * Sera Guardian

Humans

 * Bandit
 * Bruiser
 * Midget
 * Psycho
 * Crimson Lance

Zombies(DLC)

 * Zombie (swarm)
 * Defiler (slow you down with vomit)
 * Tankenstein (carries Items or weapons on his back)
 * Wereskag (can regenerate)
 * Torso
 * Zombie lance

Bosses
(In order of Appearance)
 * Nine Toes
 * Scar
 * Bone Head
 * Moe
 * Marley
 * Roid Rage Psycho
 * Sledge
 * Skagzilla
 * Mad Mel
 * Mothrakk
 * King Wee Wee
 * Rakkinishu
 * Krom
 * Jaynis Kobb
 * Taylor Kobb
 * Baron Flynt
 * Rakk Hive
 * Joseph Crimson Lance
 * Commandant Steele
 * The Destroyer

DLC
(no order)


 * Whiskey Wesley
 * Bigfoot
 * Bigfoot


 * Redjack
 * Jackie O’callahan
 * Frank 'n' bill (spelling)

BadAsses/BadMuthas/SuperBads
In the words of Randy Pitchford: "World of Warcraft has Elites, we have Badasses."http://www.youtube.com/watch?v=nWtZjR8mz9c Badasses are tougher variants of the creatures and humans. They can take and deal out more damage, but if you kill them, they often drop better and rarer equipment. However, if one starts a new playthrough on the same character, badasses become "BadMuthas". They are twice as powerful as badasses and take much more time and skill to defeat. After beating the second playthrough, the BadMuthas become SuperBads, which are assumedly twice as powerful as BadMuthas.

Badass enemies, in addition to having "Badass" as part of their name, are also often distinguished by having glowing, blue eyes. Badass versions of creatures may also gain an elemental attribute, such as a fire-breathing skag or a corrosive scythid that explodes for corrosive damage when it dies.