Peace Walker (Basilisk)

Basilisk, officially called Peace Walker, and once referred to as Butterfly, was an AI weapon developed by the Peace Sentinels. It bears a resemblance to a Metal Gear because the designs were in part based off of Soviet Blueprints of a bipedal locomotive weapon stolen by Huey Emmerich. Although technically bipedal, Basilisk's primary mode of transportation is more similar to a quadrupedic machine. It has two AIs: One is a Reptile Pod, whileas the other is the Mammal Pod, deliberately more advanced than the Reptile Pod in order to give it the capacity to launch a retalitory nuclear strike if it verifies the strike as an imminate threat. Unlike Metal Gears, however, Basilisk is completely incapable of launching a Nuclear Weapon by itself, only launching out of self defense, as part of the theory of Deterrance. However, it can be tricked into launching a Nuclear Weapon into a country that never even launched at all through false data. It also transmits the false data to third parties, as revealed by Coldman when he initiated the launch code with his dying breath. Its armanants, aside from the nuclear launcher, include an immobilization ray, flamethrowers, regular missiles, mole missiles, and various other weapons.

Peace Walker
Coldman commissioned the creation of Peace Walker (known to the Central American locals as El Basilisco, The Basilisk) in order to fulfill his vision of the perfect deterrant. He recruited Dr. Huey Emmerich and Strangelove for creating the frame for Peace Walker, and the Mammal Pod AI, respectively. However, Huey eventually found out that Coldman had an entirely different view of nuclear deterrance, as he wanted to test the deterrant to ensure that it was perfect, and refused to participate any longer in it's development.

While the weapons systems and the frame itself were complete, the Mammal AI was still undergoing construction as there was apparently a missing piece of The Boss that they needed to ensure that it would be the perfect deterrant. The Peace Sentinels captured Big Boss when the latter broke in to stop the AI, as well as ask The Boss's AI if she had any regrets for her final mission. Strangelove eventually deduced the missing piece required for the AI to function perfectly from torturing Big Boss (ironically through Big Boss not succumbing from the torture), so Coldman reveals the first target for Peace Walker's nuclear launch: Mother Base.

Big Boss does battle with the Bipedal form of Peace Walker, doing some damage to Peace Walker. Unfortunately, it wasn't enough to completely incapacitate it. It then transformed into it's quadrupedal form and headed with Coldman's Hind D towards the Nicaraguan/Costa Rican border to a United States Missile Base, with Big Boss riding The Boss's horse chasing after it. Peace Walker was able to make it to its destination, where it will launch its nuclear strike through false data after Strangelove inputted the coordinates.

However, Gálvez, or rather, Vladimir Zadornov, betrays Coldman and changes the target to Cuba, as it will cause Anti-American sentiment to spread internationally, allowing the Soviets to win the Cold War. Coldman was then shot by Vladimir. However, he missed the killing shot deliberately because he still needed the launch code. After Vladimir was stopped by, ironically enough, Amanda's FSLN group and arrested by the Militaires Sans Frontieres, Coldman, dying from a losing a large dose of blood from Vladimir's earlier gunshot, activated Peace Walker, causing not only Peace Walker to launch a "retalitory" Nuclear Strike towards Cuba, but also transmitted the false data towards various third party organizations such as NORAD, nearly causing an all out nuclear war. As Coldman died before he could give the abort code (knowing full well that he would die soon when launching it), Big Boss and Strangelove were forced to destroy Peace Walker.

However, even after Big Boss managed to destroy Peace Walker, rendering it unable to launch a nuclear strike against Cuba, it was still transmitting false data towards NORAD and the Pentagon, causing a nuclear war to become inevitable. Even Big Boss ripping out the memory cores from the Mammal Pod (which allowed him to get inside to rip the hard drives out due to not being able to forcibly remove the lock due to it being strong enough to withstand a nuclear blast) was not enough to end it, as authority for transmitting the fake data was passed on to the Reptile Pod. Miraculously, however, Peace Walker managed to get up on its own and sacrifice itself to end it by drowning in the lake, causing the data to short out from the circuits being exposed to water.

Trivia

 * The Launch Verification Code for Peace Walker is "1976."