bosses will make certain you don't enjoy your stay on Pandora
- Nine-Toes for players who don't expect backup in boss battles. While not too bad on his own, the two skags with him can be rather problematic if you've been coasting on firepower so far; they have a lot of health and are tough to take down without taking the time to aim for their weak points.
- Sledge, especially to Hunters or players who've been primarily using the sniper rifle or shotgun for headshot critical hit kills. Unless you're using a guide, it's likely you'll die against him once or twice before realizing his helmet makes him immune to headshots except for the dismally small red eyeslit.
- Wilhelm. Two levels higher than most players are if they've just cruised on the main missions (which would be enough for literally every mission so far), the first proper boss with a huge health bar on the HUD, creates 2 Surveyors at a time which constantly charge his shield while they are alive, flips train segments to call more loaders, fires freaking homing rocket salvos at you. A decent Corrosive weapon makes the fight much easier, but new players won't know in advance to bring one.
- Boom and Bewm. They're (A) the first (non-sidequest) unique enemies you fight that are noticeably tougher than garden variety mooks and armored to boot, and (B) one of them attacks you from atop a giant cannon, forcing you to actually use cover and formulate a strategy for dealing with them beyond "aim at the weak point and shoot a lot". If you don't do those side-quests, they will also be twice your level when you meet them, and even if you do match their level, they have armor before you get corrosive weapons to counter it, and have a huge cannon and a lot of backup. Oh, and as their name says, there are also two of them.
- Another example is Captain Flynt, who is armed with an incendiary pistol and an anchor as his melee weapon that he uses to perform AOE attacks that will kill you incredibly fast if you get too close. He's big, so he's just another Damage-Sponge Boss, right? Nope! You know that awesome pistol/rifle/whatever you found that sets enemies on fire so they take tons of damage? Well, guess what? Flynt's almost immune to fire damage. And he uses fire damage against you. Yikes. Even worse, he can intentionally set himself on fire, giving himself massive damage resistance. He's also surrounded by Bandits that constantly respawn till you kill Flynt. Vents are scattered around the area and shoot out fire so be careful where you step! Players at this point are at least expected to have grinded some levels to survive and dish out damage to him as well.
- Bloodwing in True Vault Hunter Mode. Her first attack is a dive towards you which you can only really dodge if you move immediately upon seeing her start it. Her second is a ground slam which requires you to take cover under one of the very few pieces of cover in the area. Third, she lands on the ground and starts trying to roast and eat you alive. The visual cues for 1 and 2 are extremely similar, any of these can take out full shields and nearly all the health of a player using a Legendary shield and a health-boosting class mod, and while she's diving is the best time to attack her! Keep in mind that she progressively gains immunity to the various different elements in the game, and you've got what is easily the hardest TVHM boss.
- W4R-D3N is yet another example, due to being the first robotic boss of the game (so no easy headshots or setting them on fire for an easy kill) with a particularly strong shield that can't be broken with just a good critical hit. Even worse/better, it's constantly building reinforcements to harass you and heal it. If you don't kill it in time, a Hyperion drop-ship will swoop down and take it away (and Roland too, who's trapped inside), forcing you to follow it to Friendship Gulag, fight through tons more enemies, and try to kill it all over again.
- The Gluttonous Thresher can be very tough if you have the misfortune of meeting him without a Shock weapon on hand, as he constantly regenerates his shields. He will also kill the robots fighting him (and you) just before they can be used as Second Winds to save you.
- Deadlift, the first true boss of the game, whose arena is tailor-made to force you to adapt to the game's new low-gravity combat. Unfortunately, this layout also makes it easy for him and his minions to run away, which can be potentially lethal if you find yourself in Fight For Your Life. Compounding the difficulty are his powerful electric attacks which will tear through your shields like tissue paper and make entire sections of the floor unsafe to stand on. Add in a beefy shield that basically forces you to bring a Shock weapon and the fact that you don't get access to a Quick-Change Station until after you defeat him, preventing you from reallocating your skill points, and you've got a boss that's all but guaranteed to stomp new players into the dirt.
- RK Mark 5, another difficult boss, can serve as this mainly because beforehand, you've dealt with quite a number of easy boss fights. The Bosun, Felicity Rampant and Colonel Zarpedon who are easy for multiple reasons, only to meet RK Mark 5, a boss that many people have stated to be easily the most frustrating and difficult boss in the game.
- Katagawa Ball, Katagawa Jr's robot. Much like W4R-D3N, you can't really set it on fire - its main purpose is to teach the player to take cover and to really use corrosive and shock elements to your advantage. While it seems like an easy boss considering that Corrosive and Shock are hard counters to its health bars, it's worth noting that unlike other bosses, this one will not summon flunkies. So if you stay in one place too long or don't take cover in time from its salvo of missiles, you will have to start over.
- The Rampager, the first Vault Guardian boss. This boss teaches you that vault guardians are not pushovers - it changes its attack patterns, becomes aggressive, and changes its vulnerabilities so you cannot just burn it down with a good fire weapon, or apply a bunch of conditions and wait it out. This boss teaches you to Attack Its Weak Point.