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Cocoon was an AI weapon developed by the CIA mercenary group Peace Sentinel in the early 1970s. Its main function was to serve as an elite attack craft.


Cocoon was one of four AI weapons developed by Huey Emmerich in Costa Rica, as part of the Peace Walker Project. As with all AI units, it was controlled by an AI pod, designated TR-Cocoon 7000. Cocoon was a towering heavily-armored vehicle, with multiple weapons lining its outer frame. The lower section possessed four treads to provide movement. The upper section could rotate 360 degrees and featured a protruding head to which the cylindrical AI pod and a large-caliber cannon were mounted. Due to its large size and heavy armor, the Cocoon's exhaust vents were lightly armored in order to prevent issues with overheating. These vents were located both on the underside of the Cocoon and on the axis for the Cocoon's upper section, near its back, although only the posterior vents were easily accessible. When overheating after sustaining enough damage, the AI's VOCALOID program also sputters while the AI weapon itself moves erratically before eventually ramming itself until hitting a solid area, where it will remain stuck, sometimes even causing the ladder near the lower portion of the body to fall due to the shock from ramming.

Along with the heavy main cannon, Cocoon had the capability to launch missiles and hedgehogs (multiple spigot anti-submarine mortars modified by Huey for surface use). They take time to fully load, however, and even then, the latter weapons system cannot actually deploy its weapons systems until the lamp section activates. It was also armed with six multi-barrel machine guns; two each on both the front and back of the lower section, and two at the front of the upper section. Smaller caliber machine guns lined the left and right sides of the lower section, five on each, along with two on the upper section, at the rear and on a large three-part mechanized arm. The arm could be used to ward off enemy infantry that may position themselves beneath the vehicle or clamber aboard the outer frame, and was also equipped with a chainsaw-like attachment that would spin around in sweeping motion.

Besides its weaponry, the Cocoon can also utilize its own body as a weapon via vertical movement, effectively acting as a giant hydraulic press.



Lower front of Cocoon


Cocoon in combat

In 1974, Cocoon was assigned to defend the entrance to Peace Sentinel's Mine Base from the Militaires Sans Frontieres. The tank-like AI weapon arrived just after Big Boss and the MSF defeated twelve sniper units that were guarding the facility's cargo elevator. Acting on advice from both Huey Emmerich, its creator, and the FSLN (the latter of whom could only supply guesswork on how to defeat it due to their not actually encountering the mech in action unlike the Pupa, Chrysalis, and to a lesser extent Peace Walker itself.[2]), the MSF caused the mech to crash on the side of the mining pit and disable its locomotion by destroying its exhaust vents. They managed to decommission it for good after tearing out the memory boards in the AI pod. Because of its decommissioning, the security panel of the doorway to the Mine Base's interior also ended up damaged due to some of Cocoon's fragments smashing into it. allowing MSF free access into the base.

The MSF later salvaged several parts from Cocoon, including its armor, in order to create Metal Gear ZEKE.


The term "cocoon" refers to the pupal stage many insects, notably moths, go through following the larval stage. Natural cocoons tend to be formed from silk or some relatable bodily excrement from the insect in question, differing from a chrysalis, which is formed from the skin of a caterpillar. Many insects imbue their cocoons with small objects like twigs, feces, and dirt to either disguise themselves or make themselves look unappealing; the Cocoon AI reflects this somewhat with its large assortment of small, large, and heavy calibre weapons scattered across its frame.

The Sandinistas' nickname for the Cocoon was el escarabajo, which is Spanish for "the beetle."

Behind the scenes[]


Analyzer scan and BDA of the Cocoon AI weapon.

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Cocoon Analyzer scan (with no BDA report)

The Cocoon bears a resemblance to the Landkreuzer P. 1000 Ratte, a design for a super-heavy tank for use by Nazi Germany during World War II, proposed by Krupp director Edward Grotte in June 1942, the tank was planned to be 1000 metric tonnes, being far heavier than the Panzer VIII "Maus", the heaviest tank ever built (weighing 188 tonnes). The Ratte's primary weapon would have been a dual 280 mm SK C/28 naval gun turret. Further armament was to consist of a 128 mm anti-tank, two 15 mm Mauser MG 151/15 autocannons, and eight 20 mm Flak 38 anti-aircraft guns.

An ultimately useless design, its large size would have rendered the tank unable to cross bridges, and travelling on roads would soon destroy them. Its top intended speed was 40 kilometres per hour, resulting in a slow, highly visible tank, vulnerable to air bombardment and artillery fire.

Another heavy resemblance would be the massive Bagger 2xx-series bucket-wheel excavators used in large scale quarry mining. Which is especially fitting since the actual fight itself happens in a massive quarry.

Coincidentally, considering its nickname, the Cocoon also was similar to the GE Beetle, a planned nuclear aircraft support and repair vehicle, in terms of overall size and function.[3]

The Peace Walker DLC included two alternate voice files for Cocoon. The first supplied it with a more human voice which was voiced by Vanessa Marshall/Yumi Kikuchi (depending on the version released). The second, exclusive to Japan, supplied the AI weapon with a voice with a Hiroshima Dialect.

The Cocoon is the only one of the AI weapons to not have been encountered by any of the Sandinistas before their destruction, as even Amanda noted in the briefing. Chrysalis was directly responsible for Chico's abduction and Amanda's injured status and was also implied to have been responsible for the abduction of several Sandinistas beforehand, the Pupa was implied in the briefing tape to have killed several Sandinista members, and Peace Walker was briefly witnessed by Chico while getting the lay of the land which indirectly resulted in his capture.

"COCOON: Human Voice
This is the alternate voice data for the "COCOON" AI weapon. V.O.: Vanessa Marshall)
When downloaded, this will change the voice for the respective AI weapon from EXTRA OPS.
―COCOON: Human Voice DLC PSN description for the International release of Metal Gear Solid: Peace Walker
"Cocoon Human voice version
AI weapon "Cocoon" another voice (CV: Yumi Kikuchi)
If download, an appropriate AI weapon's sound of EXTRA OPS is changed.
―COCOON: Human Voice DLC PSN description translation for the Japanese release of Metal Gear Solid: Peace Walker
"Cocoon Hiroshima accent version
AI weapon "Cocoon" Hiroshima accent voice version
If download, an appropriate AI weapon's sound of EXTRA OPS is changed.
―COCOON: Human Voice DLC PSN description for the Japanese release of Metal Gear Solid: Peace Walker

Cocoon also appeared in Versus Battle.

Huge, Heavily Armed, Heavily Armored
Exhaust Vents Vulnerable
Developed by Huey Emmerich, Otacon’s father, COCOON was part of the Peace Walker project and saw action defending a mine base against the MSF
―Gocoon's bio on Versus Battle


More powerful versions of the Cocoon (known as "Cocoon Type II" and "Cocoon Custom") can be fought in

Coccoon custom

Coccon Custom

Peace Walker's Extra Ops. The head from Cocoon Custom can be salvaged, which grants Metal Gear ZEKE the ability to use Cocoon's main cannon.

Battle strategy[]


Head of Cocoon

Recommended Loadout: PKM (if you have made the M60 Rank 2 (Armor-Piercing), use it instead {specs found in Extra Ops 043 - Defend Key Supplies}), LAW, Support Supply Marker, Support Strike Marker, Rations, Curry, Tortilla Chips, Soda, Mate Tea

When the battle begins, run towards the Cocoon. Its weapons are easily avoided by staying close to it. Run underneath the Cocoon and locate two exhaust vents. If you hit these with rockets or a machine gun, it will inflict heavy damage, and it may cause the Cocoon to lower its body on top of you. In that case, mash the action button to avoid being crushed. You can also plant a support strike marker underneath it, damaging its weapons and maybe even its AI pod on top. Once you have destroyed the exhaust vents, move to one side of the Cocoon and aim for its AI pod.

While attacking its AI pod, the Cocoon will attack with its Main Cannon or "hedgehog" launchers. To avoid these, simply run back underneath the Cocoon. If you can't get back to the underside of the Cocoon, use the run and roll strategy. Another way to avoid the Main Cannon is to keep running forward to avoid the first 3 attacks then run backwards before Cocoon will fire its last shot as Cocoon will fire 4 times with its Main Cannon in total. The user must beware of the chainsaw if they are too close to Cocoon.

When you cause enough damage to the Cocoon, it will crash into one side of the arena and drop ladders on each side of itself. Whatever you do, do NOT immediately climb one of these ladders. If you do, you will be cut down by one of its many chain guns. A better idea is to remain on the ground and launch rockets at the AI pod until it has just one bar of health remaining. Another strategy, if you do decide to climb the ladder: the gatling guns do not have vertical motion (save for the tail gun). Lying in prone position will allow you to avoid being hit by the gatling gun.

At that point, use one of the ladders and use the upper ladder to reach the AI pod. Hit it with a rocket or the PKM to eliminate the last bar of health. Once you've done that, attack the AI pod one more time to blow of its hatch and climb inside. You have one minute to remove the AI boards that you unlocked. Once time expires, a cutscene will show Snake leaping out of the pod seconds before its detaches itself from the Cocoon. Defeating the Cocoon causes the base door to open, allowing you to enter.

Alternative strategy[]

Cocoon Custom

Cocoon Custom in combat

This is an alternative strategy to the one above.

For players without the Bandana, load out with the most powerful rocket launcher and gun available, as well as supply markers and rations. If the battle suit is available, using it will allow two rocket launchers to be utilized along with one gun.

Head left from the starting position and there will be a ladder leading up to a small station that can be climbed up. If this is done immediately, it is likely that the player will be hit by the Cocoon's heavy cannon, so ensure that rations are equipped should the entire Life gauge be depleted in one hit. Move to the railing on the left (when facing towards Cocoon, it is the right), and make sure to stand just behind the railing. From here, Cocoon can be attacked without fear of getting hit by its gunfire, even though it appears as if it can.

When Cocoon fires tracking missiles, move near the ladder that was climbed earlier (when facing towards Cocoon).

When Cocoon prepares to fire its heavy cannon, move back towards the rock wall, squat, then fire your weapons at the AI pod.

Following this strategy correctly, to consume any ration at all with this strategy.

Continue doing this until the Cocoon has only one bar of health remaining. If a weak rocket launcher is being used, a couple of rockets can be fired at it prior to heading up the ladder on Cocoon's side.

Upon reaching the top of the Cocoon, shoot at the AI pod to eliminate the last bar of health. If the two machines guns prepare to fire, lie down flat by holding down on the D-pad. If tracking missiles are launched, head to the back of Cocoon's head to avoid them.

If the player has the Bandana and a powerful rocket launcher, an S rank can be more easily achieved, and the mission can be completed within 5 minutes. This is desirable if the player is aiming to procure the Cocoon Head.

Harvesting Cocoon Head in Cocoon Custom mission[]

It is easiest to harvest the Cocoon Head when equipped with the Bandana.

Use the alternative strategy above along with a powerful rocket launcher. Make sure to aim at the top of the AI pod so as not to damage any other part of the Cocoon. Damage to the pod will be displayed as white numbers only, whereas damage to other parts will be displayed as numbers and colored letters (A, S, C, and M).

When Cocoon goes berserk at four bars of health, wait until it is stable so that the AI pod can be safely aimed at again.


Ordinary/Type II[]

  • "Main Cannon Loaded" (when about to fire its main cannon)
  • "Commencing Area Attack" (when about to fire hedgehogs)
  • "Commencing Sweep Attack" (when about to sweep the area with its chainsaw/gun arm)
  • "Missile Target Acquired" (when about to launch missiles)
  • "Thermostat Malfunction Detected" (when 2/3rds of its HP are depleted).


"This is going to hurt" (when about to fire its main cannon).

"Die" (when about to fire hedgehogs).

"I’ll smash you" (when about to smash the player).

"You think I’ll let you get away" (when about to launch missiles).

"Now I’m really pissed off..." (when 2/3rds of its HP are depleted).

Other appearances[]

Cocoon also appears in Metal Gear Solid: Social Ops as a boss as well as a series of cards. In addition to both its ordinary/Type II forms as well as its Custom Forms, there were plans to give it a golden card, although the game was discontinued before it could see release.

In addition, the player can also develop a Cocoon as their Metal Gear in the Mother Base development game in the Ground Zeroes app, accessible after upgrading a Hangar strut to Level 5. It costs 400 materials to create. The player can also unlock a Custom version of Cocoon by obtaining a score 60k+ on Hard Mode of Classified Intel Acquisition while connected to the app.


See also[]

Notes and references[]

  1. ^ a b c
  2. ^ Amanda Valenciano Libre: That is el escarabajo - the beetle. Even we don't know the escarabajo's weaknesses. // Naked Snake (Big Boss): That's not what I wanted to hear. // Amanda: You could try asking that scientist... Huey, right? This is just common sense, but once it fires a missile, it must take time to reload. And moving a machine of that size must require the release of considerable amounts of heat. Another option would be to take out its weapons. Sorry if I wasn't much help. // Snake: No, you've given me some ideas.
  3. ^