Armor Unit

The Armor Unit is the fifth and ninth boss faced in Metal Gear Solid V: The Phantom Pain.

Description
The Armor Unit is first faced in Episode 16: Traitor's Caravan, where four of them spawn around the cargo truck the player is trying to extract after they get close to it. It is entirely possible to completely avoid fighting the Armor Unit all together by waiting for them to shamble away from the truck and crawl in to Fulton it, or use D-Walker's Fulton Ballista to Fulton it from a distance. To actually fight them, all you'd need is some dodging skills and a rocket launcher. D-Walker's gatling gun is also one of the easiest options, as it mows down each Skull in a matter of seconds. Attack-wise, the Armored Skulls function almost identically to the Mist Unit, but with two big differences: they have an extra health bar due to their metallic skin and they can throw the boulders they spawn, though this attack takes incredibly long and leaves them extremely vulnerable.

They are again faced in Episode 29: Metallic Archae where the player is forced to fight them and where they're surrounded by zombies.