Intercontinental Ballistic Metal Gear. A nuclear missile launch platform that can fly on a ballistic trajectory to infiltrate any country in the world and deliver its multi-warhead payload. The ICBMG's design concept resembles a MIRV rather than a simple missile. Its solid rocket booster propels it into space; when it arrives over its target, it reenters the atmosphere. At an altitude of 3000 feet, the Metal Gear unit separates and parachutes down to earth, where it launches miniature nuclear warheads. The unit's armor plating is tougher than a tank's, making it hard to destroy from the outside.
The ICBMG was developed by the rocket scientist Nikolai Sokolov. Gene used it as FOX's trump card to threaten the US and Soviet Union. But the rocket connector was hit in an attack by Naked Snake and his unit, causing it to burn up upon reentry into the atmosphere.