How to defeat the Aether Worm Orcus in MW3 Zombies (Defeat Zakhaev)

The final mission for Act 3 in Modern Warfare 3 Zombies puts you up against the monstrous creature—Orcus. Your objective near the end of the deployment will be to defeat the Aether worm boss, and here's how to do so.

Best way to kill the boss worm Orcus in MW3 Zombies

Before anything, you need to prepare yourself and have good gear because this is the main bossfight in the MWZ storyline. Here are the items I suggest bringing into the match to fight Orcus (especially if you're solo):

• The Ray Gun wonder weapon is easily one of the best equipment against the worm boss, but it's difficult to come across.
• Other recommended weapons are LMGs and Assault Rifles like Pulemyot 762 and Holger 556. I didn't keep any secondary weapon as sprinting is faster when fists are out.
• Pack-a-Punch your weapon to at least level 2 and preferably level 3 to deal significant damage. Furthermore, applying Legendary or Rare Rarity also helps boost its effectiveness.
• Two or more Self-Revive Kits for extra lives in the fight.
• Perk-a-Cola Cans that I suggest consuming before infiling are Speed Cola, Stamin-Up, Jugger-Nog, and PHD Flopper.
• If possible, bring the Tier 3 Pet Hellhound to take care of lesser threats.

Related: All MW3 Zombies Easter eggs

Normally, you should be using Decoy Grenades as your tactical equipment in MWZ as they completely distract Zombies' attention from you for a short while. However, Experimental Gas works wonders against the worm boss and damages it quite a bit if you throw the tactical near its body on the ground. Therefore, gas grenades are the way to go to defeat the Orcus.

The Aether worm is a bullet sponge, hence you'll have to keep shooting at the beast for a long duration to bring it down. Target the glowing purple flesh under the armor openings as that's where it hurts Orcus the most. Simultaneously, keep throwing Experimental Gas at it for extra damage. But remember, you're not the only one on the attacking side here.

The Orcus has a few tricks up his sleeves and when it attacks, all you can do is dodge and get cover inside the surrounding buildings. The worm will shoot deadly laser beams out of its mouth, which can instantly down you. The beast can also burrow underground and pop back up out of nowhere, so try to anticipate its path and stay out of its way.

In case you get caught in the attack, it'll launch it up in the air breaking your armor plates and you'll have to open your parachute before hitting the ground. Finally, the monster can smash its head on the ground dealing damage to your operator. While all of this is unfolding, waves of Tier 2 Zombies and fast-flying orbs will attack you, so make sure to eliminate these first.

Keep fighting and continuously replenish your ammunition and tacticals from the numerous Ammo Caches in the area. You'll never run out of Experimental Gas to throw if you keep visiting all these crates. This is all the information you need to keep in mind in order to take down the boss worm Orcus easily in MW3 Zombies.

How to start the Defeat Zakhaev mission

To start the mission, board the chopper at the designated exfil point that says Defeat Zakhaev. After going through all the enemies and infiltrating the facility to destroy the Aetherium enrichment devices, you'll be asked to reach the Neutralizer site. Don't worry about destroying the enemy helicopter there as the Orcus boss worm will eventually do that if you wait for a while.

Stay tuned to Pro Game Guides for more Call of Duty: Modern Warfare 3 content. In the meantime, head over to our article on All Makarov’s Return event rewards in MW3.