Crawmerax the Invincible

Crawmerax the Invincible is a boss in The Secret Armory of General Knoxx. He appears in the mission You. Will. Die. after you finish the main story included with the DLC.

Information
One of the hardest bosses, if not the hardest boss ever in Borderlands, Crawmerax is at level 64 while players are capped at a mere 61. Even a four player party will have a very difficult time besting this foe.
 * Crawmerax the Invincible is a fully grown Crab Worm, with a heavily armored, spiked shell. The Larva Crab Worms seen in the Lost Cave and the Trash Coast are puny by comparison. He looks like a titanic grayish-brown version of a Larva Crab Worm with glowing purple critical-hit spots on his body.
 * He is surrounded by level 61 and 62 Green Craw Worms, Craw Maggots and Armored Craw Worms.
 * To reach Crawmerax once inside his lair, you must go up a very long lift to the top of a plateau.
 * He has a chance of dropping the super-rare Pearlescent weapons.
 * Crawmerax is level 64 in both playthroughs. However, he and his minions seem to have much less HP in the first playthrough. This is probably for players to get the same damage reduction, encountered when facing overlevelled enemies.

Strategies

 * 1) (see video #1) He is level 64 on both playthroughs and is the toughest enemy in the game.You can only damage him by getting critical hits (shooting the eye and other "purple" areas). Therefore, it is best to use a gun that can scatter numerous shots over a large area such as SMG's. It's recomended to attempt this in a group due to the fact that it can down you in one hit and if all members of the group leave the top area he regains all his health. Therefore, it's best to have at least 1 Siren in the group so that if everyone else dies they can hide from Crawmerax and his minions until the rest of the party can regroup. In addition, having someone in the bottom area would be useful so that they can call the elevator back down - it takes about 20 seconds for the elevator to go from the top to the bottom and if you have to call it back down that's 40 seconds. This means that if you are downed and only one person is left then they will have to struggle to survive for 40 seconds as opposed to 20 seconds. As Crawmerax only regains health when your whole group leaves the top area, if the elevator is already at the bottom it will greatly increase the chance of getting to the top before your last group member dies- and thus, Crawmerax healing completely.
 * 2) Generally, a good weapon to use against Crawmerax is the Eridian Thunder Storm. Its shotgun like spread effect gives you a higher chance of hitting the critical areas once or multiple times. Also, since the thunder storm's bolts have a bouncing effect, if you aim near Crawmerax's 'Armpit' area when he is facing you, most of the bolts will reflect off him and hit the critical areas on the back of his claws. Having two or more players with the thunder storm will allow you to keep a flow of bolts in the air (i.e : player 1 fires until depleted, then player 2 fires while player 1 is recharging, ect.). Another excellent weapon to use is a Chimera – the multiple damage types can be a great help against all crab worm types and Crawmerax himself. Still another great weapon to use is an Orion. If you aim just right, a little bit below the purple spot on his back, you get all three ricochets to hit. It's high fire rate, accuracy and magazine size are also all quite useful. SMGs with an electric element are also effective against Crawmerax.
 * 3) A general strategy is to use 2 Sirens, 1 Soldier, and 1 Hunter. The Sirens will be the "survivors" - when everyone else is dead and trying to get back up, they can use Phasewalk to hide themselves until then. The Sirens should use Defender class mods for the shield capacity bonus or the catalyst class mod for the team cooldown reduction. The Soldier is the support. He would use a "Support Gunner" class mod to regenerate ammo and overall assist the team using his skills. Roland will most likely end up being one of the people doing the most damage. Lastly comes the Hunter. Mordecai uses a "Survivor" class mod, preferably one with the best possible Health regeneration. The Hunter will be the second person dealing most of the damage. Players should keep in mind that any combination of classes can defeat Crawmerax.
 * 4) Another strategy is to have everyone go up at the same time at the beginning. The first person to get downed should immediately respawn prematurely (unless it is easily possible to get a Second Wind) and queue the elevator to come down. Depending on the condition of the people still above, he will either wait for the next person or two to die and then go up, or go up right away. When two or more people are waiting for the elevator, whoever is up top should do one of two things; if they're a Siren, Phasewalk and sprint around the arena. If they're not a Siren, they should hug the rock arches on the inside to prevent major damage from Crawmerax until at least one Siren makes it back up. Getting a Second Wind can be absolutely essential to consistent success and understanding the weakness of any of the minions that attack you can help you get back up from any attack. Examples include using a Defiler revolver on armored worms, a Hellfire SMG on green worms and an Orion sniper or other strong shock weapon on maggots. Plan ahead and make sure your entire team has the proper equipment. Using this strategy, you can slowly whittle away at his health until he goes down, although it is still very, very hard. Make sure your team has good communication and a clean connection (more important than you may think), or else this will get messy quickly. Do not let the pressure of being up there alone impact your performance.
 * 5) Fight on the ledges where you spawn. As long as you stay crouched, you can avoid any push-off moves Crawmerax or the spawn will do to you. Juke any maggots and get them to fly off the ledge. If Crawmerax gets too close to you, duck down and allow a friend (if you aren't soloing, this strategy was done with a Gunslinger Hunter and a Mercenary Siren) to take aggro (get Crawmerax to chase him). Avoid the spawn, hit the purple areas, spam med kits/etc, and most importantly, hope you will win.
 * 6) One easy and heavily exploited glitch is to run near one side of the circular wall of cliffs surrounding the plateau when you expect Crawmerax to jump, so that the force of his descent propels you onto a ledge on top of a cliff, allowing you to remain on the plateau without sustaining damage and preventing Crawmerax from regaining health when your allies respawn. You can be hit by ranged attacks, however, but if you do not attract Crawmerax's aggro, it should not be an issue. If anyone happens to fall off, back into a corner on the ledges and relax for a minute while your partner gets back up and in position before firing; the person up top still will need to get Crawmerax's attention to give your partner time to get into position. Communication is key. Crawmerax has been bested in single player with Lilith using this strategy. If you are hit by acid, phase walk until it runs out, let Phasewalk get near full recharge, and keep firing. Do not fire until Phasewalk is almost back up. Apparently in the corner you are hidden, and until you fire you are invisible to Crawmerax, making it easy to keep dodging him until you whittle his HP down. This typically takes about 10-15 minutes per kill. After a while, the spawn stop coming up so often, and so a team can actually go out to the middle area and spread out. As he goes towards a person another would shoot him in the back to distract him and deal some damage to him. If anyone goes down a Soldier can put down a turret or someone can distract him while the team revives them. The only real worry is his area of effect jumping attack that can hit everyone. Soldiers with Cauterize are recommended when doing this. This strategy can be useful if you don't want to lose any loot, as some of it can fall off the ledge if Crawmerax is too close when he dies. Have two people go to each ledge and have another person as the reviver/ person who kills the grunts. Follow this Strategy Video
 * 7) It is possible for Lilith to solo Crawmerax by taking advantage of the Phasewalk ability to get out of situations and heal before attacking critical areas. However, the loot will not be as good compared to more people.
 * 8) Another good weapon to use is the Chopper. If 4 people with all support gunner open fire on him it will eat away his health.
 * 9) If you're Brick in a party, a good but sacrificial strategy is to get a high level Centurion mod with +4 bonus to Die Hard, with max Die Hard on the skill tree, let Crawmerax kill you and keep shooting him to attract his attention while your team gets behind him and unloads bullets at the distracted Crawmerax.
 * 10) The easiest way to kill crawmerax is with the Siren, you can Phasewalk over to a gap on the far left and none of the enimies will attack you so you can take out most of crawmerax critical point very easily, this can be done with other classes but is much easier with the Siren.
 * 11) Another set up that is quite effective is a hunter with a sniper class mod that regenerates sniper ammo and the orion sniper (at least level 48 version is recommended). It is especially useful because even when crawmerax is facing you it can hit his critical spots through the front of his claws. Just get some cover behind a column or soldier's shiled, and start unloading on him. It should take him down in a matter of minutes if you can get constant hits on him, but it will probably last about an hour with dying and running adding minutes to your time. It makes things much easier if you have a siren character waiting down bottom to come up when crawmerax's back is left. Have them phasewalk as soon as they reach the top. Then have them get behind him, and unload on his back. When crawmerax turns around hit him with the orion. You can combine these two strategies as the soldier if you use a Support Gunner mod, by first throwing your turret as a distraction. This will give you enough time to make it over to the gap.
 * 12) If you're a soldier, you can go to the far left aclove where he can't see you. From this point you should be able to slowly whittle away his health. When all the criticals are gone in the the front, you can jump, touch the edge of the plateau, throw out a turret, and jump back into cover. Crawmerax should either go towards it and melee it or shoot acid. If he melees it then he may try to melee you. If he tries to melee you, just stay in cover and duck. He should head away eventually, and when does you can shoot his back critical spot. If he shoots acid then after you (most likely you'll die), you should try to get a second wind. If you get a second wind, you should be able to shoot while he walks away. This may take multiple tries as this tactic isn't foolproof (see video #2).
 * 13) If you are weapon farming, set up or join an online game with 4 people to maximize your chance of getting a rare weapon. A good method is to have a group spread out to the 4 corners of the arena and have one person go in the glitch spot to distract him and to survive if your teammates die. That is the basic jist, and dont forget to have a support gunner in your group and aim for the purple spots. This can be done with a group of three 61s and one 50 or above.
 * 14) If you use the strategy (to the left) from 0:00-4:50 you will be stuck, unable to attack his back in the glitch. This is when you use the Leviathan's arch to attack the critical on his back. While the way to attack his back with the spiral bullets is perfectly fine attaining the gun with them is hard. You can always get a new Leviathan by Rakk Hive loot.
 * 15) A final strategy that works but is hard to use is to have four sirens whose skill tree utilizes phasewalk cooldown reduction and phasewalk healing. Each of the sirens should use the Catalyst class mod, if one of the sirens has a 30 team cooldown reduction and the others have 26, the team should duplicate the class mod. The team should try to phasewalk around Crawmermax shooting him in his weakpoints. If Crawmermax gets too close, phasewalk away to a safe location.
 * 16) You can use the strategy on the right and not have to use a Leviathan or weapon with spiralling effect, you can use any normal Rocket launcher (explosive). To hit the spot on his back, you must simply shoot the large spikes protruding from his back. This may require some guess and check, but works very well as every shot gets between 400-600 damage (damage doesn't seem to change with more powerful launchers).
 * 17) The best solo strategy for a hunter is to get a 600-700 Penetrator (a full auto sniper) and shoot at the base of the critical hit points (I killed Crawmerax in minutes using this strategy). Also, such weapons as a Jakobs Skullmasher or an Hyperion Invader will be the best choice, especially because of the critical damage enhancement and the capacity of scoring several critical hits in shot/bursts before Crawmerax can turn or react: the former, however is the best choice, since the latter has the nasty habit of chewing up all of the sniper rifle ammo really quickly, and should be coupled with a Ammo Regeneration Sniper MOD.
 * 18) To solo with the Siren: Upon arriving at the top of the plateau, wait a few seconds for Crawmerax the Invincible to approach, to where he is standing give-or-take in between the two pillars in the center of the arena. Once you feel he is in position, Phasewalk to the safe-spot (as highlighted in the video on the right) and pull out an SMG with high power, high rate of fire, and low accuracy. The low accuracy allows for a better spread of damage, allowing you to hit two pincers, and on occasion, his eye, without moving your reticule at all. However, it is recommended to use the Hyperion Bitch if possible, due to its increased critical damage. Use the SMG of your choice to destroy all 4 pincers, and possibly his eye. Alternatively, his eye can easily be taken out with a high-powered sniper rifle, revolver, or an accurate shotgun. Now comes the main problem: HIS BACK. So, If you're anything like me, you didn't hold onto ANY weapons that have bullets that ricochet. NOT a problem. See the stone arch to the right? So does Crawmerax. He cannot see you if you hide behind it. This is more difficult than the legs, as you DO have to face his minions. Before you do anything, be sure you have a high powered weapon, 1000+ damage per shot if possible. If not, no problem, but he will not go down as fast. Prepare your weapons, reload anything you may need to fight the minions, and make sure your final-kill weapon is fully loaded. Now: remember your target is the stone arch. Jump up out of the safe spot, wait a moment. Crawmerax should walk a few steps toward you. As soon as he raises up for a ranged attack, Phasewalk. Hide underneath the stone arch, where you cannot see him. Take out your power weapon. slowly inch out to the side until you can a small corner of the purple spot on Crawmerax's back. Aim true, take your shot. Depending on your weapon, he may go down in as little as 2 shots! If he turns around before you can finish him, do not panic! Simply phasewalk back to the safe spot, wait for your phasewalk to recharge, and prepare for another attack.

Weaknesses

 * Green Craw Worms are weak to Fire damage and their eye is their main weak point.
 * Craw Maggots are weak to Melee damage and Shock damage. Their eye and underbelly are their main weak points. A high-level(Lv48+) Thunder Storm can kill them in one or two shots up close.
 * Armored Craw Worms are weak to Corrosive damage and their critical points are the same as Crawmerax's.
 * Crawmerax is weak to Shock damage and his weak points are all highlighted by purple glowing spots- More specifically, his back, his eye and the backs of each pincer. Although the orbs that are the weak point of each pincer are on the back, they may also be hit from the front by aiming at the joint where the two halves of each pincer meet. Many shots fired at this point will miss, but some will get through, so high fire rate weapons are best for this purpose.

Glitches

 * There is a glitch where Crawmerax himself will fall off the cliff and become trapped. While it's possible to kill him from this position, the drops will be completely unreachable.
 * Just before you go through the red barrier while going up with the elevator, it will seem like you are being squished. If you jump at the right moment, you'll be superlaunched into the lair. Usually, spamming the jump button works.