Crawmerax the Invincible

Crawmerax the Invincible is a boss in The Secret Armory of General Knoxx. Killing Crawmerax unlocks the "Vincible" achievement/trophy. He appears in the mission You. Will. Die. after you finish the main story included with the DLC. He also has a very high chance of dropping new super-rare weapons called "Pearlescent weapons". One of the hardest bosses ever, Crawmerax is at 64 while players are capped at a mere 61. Even a four player party will have a very difficult time besting this foe.

Information
Crawmerax the Invincible is a fully grown Crab Worm, unlike the Larva Crab Worms seen in the Lost Cave and the Trash Coast. He is surrounded by level 61 and 62 Green Craw Worms, Craw Maggots and Armored Craw Worms. When approaching the travel point for his lair, the ground will shake and you can see many warning signs.

To reach Crawmerax once inside his lair, you must go up a very long lift to the top of a plateau.

Crawmerax is massive and has a heavily armored, spiked shell. He looks like a titanic grayish-brown version of a Larva Crab Worm with glowing purple spots on his body.

There are several skeletons similar to the that of Crawmerax all over the deserts in Secret Armory of General Knox, implying he is the last of his kind due to his hibernation.

Strategy
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 - ie. SMGs. 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 15 seconds for the elevator to go from the top to the bottom and if you have to call it back down that's 30 seconds. This means that if you are downed and only 1 person is left then they will have to struggle to survive for 1 minute as opposed to 30 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.

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 are Chimeras- their 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.

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 Defender class mods for the shield capacity bonus. 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.

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.

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.

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

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.

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.

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.

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.

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.

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 join 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.