This telepresence unit, whimsically named the "Metal Gear mk. II" by its inventor, Otacon, for its vague resemblance to Metal Gear REX, is a remote-controlled robot that Otacon uses to get a direct view of the battlefield. It has a deployable screen that can display the face of Otacon during a conversation with Old Snake, or the face of another person sending a message to him. It also has a flexible manipulator tentacle that allows Otacon to minimally interact with the environment around him. The tentacle has three swappable tips that serve different purposes; a set of grasping fingers allows it to pick up small objects, a computer interface plug allows the mk. II to physically connect to computer systems so that Otacon can remotely hack them, and a high-energy taser allows the machine to non-fatally electrocute enemy combatants.
Although the majority of the time, the mk. II is controlled from the Nomad by Otacon, Snake can temporarily take manual control of the device (amusingly, he does this with a remote that looks suspiciously like a Playstation 3 DualShock 3 controller) and steer it around to scout out an area or tase enemy soldiers, knocking them out so Snake doesn't have to deal with them. He can also electrocute himself if he is feeling particularly silly. Curiously, it is only when in this mode that a battery bar appears; since Otacon can control the mk. II for unlimited periods of time without it running out of power, this suggests it is the remote control that Snake is holding that requires energy. If detected by enemy forces, the mk. II will be kicked and pistol-whipped; although it cannot be destroyed, if the player puts it in danger too many times, Otacon will retake control and tell Snake to take better care of expensive equipment. In addition, when Snake is controlling the mk. II, it has a limited effective range; close in on that range and the screen goes fuzzy. Pass that range and the remote will cease to function, Otacon will retake control of the mk. II, and the player's control perspective will return to Snake.
The mk. II is equipped with a small cloaking device; although OCTOCAMO is considered superior to a cloaking device when dealing with Old Snake, because many enemies have the ability to see in infra-red, rendering it useless, the small, inorganic mk. II is almost totally invisible on infra-red sensors, so the cloaking device serves the purpose well. Although the robot only appears when Otacon needs to talk to Snake or when the player takes control of the machine, according to the story, the mk. II closely follows Snake at all times, its cloaking shield activated.
- This device is named after Metal Gear mk. II, a sentient robot character from Hideo Kojima's early game Snatcher, who was in turn named after the war machine from the original Metal Gear.
- The Metal Gear mk. II is lost in Act 3 of Metal Gear Solid 4, "Third Sun", after Otacon sneaks it onto Liquid Ocelot's escaping boat in order to listen in on his conversation. After a few important plot points are revealed, the mk. II is discovered by Vamp and quickly destroyed. After this, it is replaced by the Metal Gear mk. III, which is identical to the mk. II in every way, except that the mk. III has a brown casing, not a grey one.