Secret Marine on The Covenant

The Secret Marine on The Covenant can be found in Halo 3 ' s Campaign level The Covenant, and takes the form of a Marine hidden in a hard-to-access location.

The Marine only appears on single-player Local Play, and can be accessed using a or a Prowler. Sometimes, two or more Marines will appear. It is suspected that the faster you get to the Marine, the more Marines you will find. There appears to be a kind of "time limit", after which the Marine will not be present—whether he disappears or heads to another location is unknown. Once you encounter him, though, he will never leave his position.

Ghost
Start at Rally Point Bravo. Grab a Mongoose and drive straight ahead at full speed. When you get to the part where a Marine says, "Citadel in sight". Get off of your Mongoose and grab a Ghost as soon as possible. Drive the Ghost ahead as normal. When you approach a tunnel, turn right and climb straight up the mountain. There, you will find the Marine(s).

Prowler
You can also do this in a Prowler - steal one from the Brutes in the area before the tunnel. Once you get to the ridge on the top, you will need to pick your path carefully—some parts of the final ascent are too steep for a Prowler. Also, the Prowler is very slow, so you may reach the top only to find that the Marine has vanished.

Trivia

 * The Marine(s) will usually change faces every time you go up the mountain.
 * It should also be noted that the weapon the Marine carries will vary. Usually, the Marine(s) carry Assault Rifles, but they can also wield Rocket Launchers or Pistols.
 * The marines may also be there as placeholders for reinforcements that will replace the warthog's crew when it's destroyed.
 * The quicker you get up, the more marines there are.